After reading a million reviews, I still couldn't decide on a portable playpen, so I ordered the Regalo, D.LIN, and BabySeater since they had free returns.

8-Panel Regalo
Pros:
+ Easy to set up and take down
+ Larger space (if you have room for it) ~71" corner to corner and 65.5" edge to edge. The inside is a bit smaller since the edges are elevated off the ground, so flat surface area is more like 61" x 59".
+ Seems pretty sturdy, although I am wary about longevity because of the negative reviews.

Cons:
- No padding on the bars with small bolts at the intersections.
- Velcro stitched to the mesh felt kind of sharp and seemed like it could snag and damage the mesh in the future.
- Might be too big for traveling or if you have a small space.
- Bottom panel is super thin with no padding at all.

I ended up returning it because I think it is too big for my travel needs and the non-padded bars seemed slightly hazardous.

D.LIN
Pros:
+ Comes with a separate pad for the bottom. It is thin and not the best quality, but it's nice that it's separate for easy washing.
+ Comes with straps to tighten the poles before putting it away.
+ Has slight padding on the bars and padded circles at the intersection of the poles. It's thin, but enough to make a difference if a kid runs into it or falls.
+ The size is a nice medium size between the other two. I measured it to be 59" corner to corner and 51" edge to edge (interior of 56.5" x 48").

Cons:
- Doesn't really lock open like the other two.
- It's the most tedious to set up and take down. You need to buckle/unbuckle all of the straps at each leg to open and close it. For strurdiness, you'd need to attach the suctions too, which wouldn't work for carpets or outdoors. (I find the photoshopped picture with it sitting in the sand pretty hilarious).
- The carrying case has a side zipper, which is a little more tedious to put in than the other two that slide over the top, and a few reviews mention the zipper breaking.
- In one of the pictures, it says that the mesh is removable. It doesn't include instructions on how to remove the mesh, and from what I can tell, this can't be done without removing a lot of screws and hardware.

I really like how they padded the poles without adding bulk to the playpen, and I wish the other two would do the same. However, I returned it because it didn't seem as sturdy and was much more tedious to set up and put away.

BabySeater
Pros:
+ Easy to set up and take down.
+ Has thin padding at the bottom (although would still need more padding underneath for hardwood/tile floors).
+ Lack of cross bars means less chance of baby bumping into it; no intersection with nuts sticking out.
+ Zippered door means kids can go in and out instead of trying to climb over it; zip on the outside only means kids can't escape from inside.
+ Better quality overall (stitching, material).
+ Mesh removal seems the easiest on this one.

Cons:
- Smallest of the three at 54" corner to corner and 47" edge to edge (interior was about the same). I wish it was a little bigger -- 60" would be nice.
- Most expensive of the three.
- Wish it came with an inflatable mattress to put inside for more padding and easy removal for cleaning.
- It would be nice if the poles had padding on it like the D.LIN.

Amongst the three, I think I like the BabySeater best. I just wish it were a little bigger. I am intrigued by the Pop n Go by The California Beach Co, but since it's not free returns, and it's significantly more expensive, I may stick with the BabySeater.

I needed something to wrangle my toddler while sleeping during travel. She is 2.5 years old, just under 3' tall, and weighs 31lbs. She hasn't figured out how to get out of her crib or over baby gates so I figured this would work knowing a travel cot, regular play yard, and folding crib would not. She tried to sling her leg over the top of this and couldn't reach even while pulling herself up and she is strong.

She could sit comfortably or sprawl out in her sleep. (See photos.) She sleeps with 2 books, 5 stuffed animals with a variety of blankets and she slept like a champ every night. The photo with the arrow pointing at her head shows her all sprawled out laying on her back. The other one she is sitting up reading her book.

You'll absolutely need padding as the bottom sits directly on the floor with basically no padding. We purchased a sleeping bag and added her extra blankets in. She can work zippers so we pushed that up against the wall and didn't point it out.

It was a bit bigger than I imagined so it really did work out well! When folded up it's not overly huge and in the carrying bag it is super easy to travel with. READ THE DIRECTIONS on how to open and lock it. It's not at all hard by yourself but it was easier if two of us were locking it at the same time.

I have recommended this to multiple people already who move and travel a lot like we do.

Love it! Came already assembled, just had to click 2 spots in place and done! Soooo much easier than any playpen we've had! Both my 3 yr old and my 9month old love it! They both fit with lots of room to play and no it's not over the top big either.
It doesn't have any padding, which we expected based on reviews, so we just placed it on top of our foam mat that we already had at home since it sits basically on the floor.
We will be adding pool noodles to the sides as other reviewers had recommended for head safety for our 9month old. Such an easy fix for more safer play area!

Update:
My 9month old has so much more fun in this play pen (which is much, much bigger than the standard size graco playpen). Since he started climbing, it's been hard to contain my little guy! Especially in the the graco playpen since he would stand up cruise around and started to try to put his arms and elbows over the whole rail and lift off with his feet! He's all over the place and now cruising! So you can imagine having to carry him around so he doesn't get into mischief or worse take a hard fall. This play pen has been that extra help I need to set him down, while I do the little things around the house when I don't have have the extra hands to help (my husband 😅) He can't pull himself to stand in there (I'm sure he'll eventually figure out a way though 😂) and I'm sure being that it's a wide open space for him to have his toys in there and still crawl around is what makes him content. Worth the extra money!
Positive update!
My son is now 19 mos and this has been THE BEST life saver! I highly recommend this for anyone with a mischievous toddler like my son who gets into everything 😂 I can't turn my back for one second and my son is getting into something! He's a runner too, so he's climbing up on everything, running everywhere. This gives me that peace to knowing he's ok to play with his toys in this very roomy playpen , if I need to grab something from the other room or what not.

This guy is huge, in the best possible way!
Super easy to move and open and close, even while holding the baby. That's thanks to the two red quick latch and release buttons, which also have a guard so bigger kids can't accidentally collapse it.
It's very sturdy and big enough to hold me and my husband and baby.

There isn't really any padding to the bottom, so we bought a play rug on Amazon that fits perfectly in it for some extra cushion. We're now using this as a ball pit too, which our daughter loves. She can roll and crawl all over this thing and not get super bored from being confined.
Of course, it is mesh siding, so be careful with dogs.. ours tore some holes in a side trying to get to a rolled up diaper we accidentally left in it for a few minutes. 🤦"â'€ï¸ I found some patches online, so we are going to order those and try to patch it so we don't have to buy the while playpen again.
Overall, the pros are soo awesome that we don't care about the fact that it got a couple rips and needed the padding.

I have been anticipating this for some time! We are going on a family trip and wanted something easy, durable and lightweight. I was looking into so many travel cribs/playards and found this in my research. I am so happy with this product. It is extremely easy to put together, it's large enough for naps, play and small enough to fit in snag of our rooms. This is very well made, quality and it is lightweight! I love the zippered opening and that it is flat on the floor. I can sneak in and nurse my son for. Dream feed and get out. Awesome product!