Does everything I wanted it to do and more. I had a pretty difficult checklist and this is the only product I found that meets ever need.
I wanted:
The ability to wear a single set of ear buds or headphones for multiple purposes
The ability to use a high quality, external, condenser microphone for multiple purposes
The ability to listen to audio from a PC or Android phone
The ability for any audio I listen to to be in sync with associated video
The ability to hold phone calls using previously mentioned equipment from a PC or Android phone

I can plug this product into my desktop with a USB cable and all these requirements are met
I can unplug the USB from the computer and use Bluetooth to connect to my Android phone and all these requirements are met
I do not need an in-line power adapter for a condenser microphone to work (Tested with Pyle-Pro PMEM1 Headworn Omni-Directional Microphone (3.5mm / 1/4''))

The ultimate test for me was driving in a car with a loud exhaust going 50 MPH while on a phone call and the caller on the other end saying they heard me loud and clear with little to no background noise.

Having used many Sound Blaster products in the past, I expect all other functions will work very well. I have noticed that the battery is a bit slow to charge, so I wouldn't plan on using this as a backup charger for your phone in anything but an emergency, but as I will have this plugged into my computer or a power source half the time I'm using it, this isn't a critical issue for me.

I've had this for all of two days, so I may edit this later. So far...

Pros:

Works right out of the box without drivers. I mean, it works better with the drivers and software, but it's slick that I get high quality sound the instant I plug it in.

USB charging of the battery. mine came charged at 50%, so I was able to use it for the first 9 hours solid and let it charge after.

The EQ is solid

The voice options are hilarious! I don't know about useful, but they are fun!

swaps uses easy. It works on my laptop, desktop, and phone well and with almost 0 effort.

Cons:

Super sensitive mic drivers. I have the same headset I've been using for months, but suddenly not only can my friends hear me type, they can hear themselves - even though their voices play through the headset instead of my desktop speakers. It's not the end of the world, and as I play around with the settings I may overcome it, but I had no idea how sensitive my mic was until I used it with this.

Hiss. I got this as an emergency replacement soundcard, so it's not a deal-breaker; still, it seems odd that a device that is supposed to add to audio clarity has the background noise.

Overall:
The best soundcard I've had for this price, and one of the best I've had period. I like this better than the Audigy I used to have and I paid *way* more for that. For the price, it's solid and I would buy it again if the need arises.

I bought this DAC to use with my Galaxy S7 and ATH-M50x headphones as well as an external sound card for my laptop, but after testing I noticed the E3 does not have a flat response curve after measuring it with REW on my laptop. It starts rolling off bass at 100hz down to 20hz when connected via Bluetooth to my S7. Surprisingly the direct output from the Galaxy S7 3.5mm port is dead flat from 10hz all the way up to 20,000hz, which is great.

The Sound Blaster Central android app doesn't allow for any modification of the eq on the E3 which would help overcome the stock curve. I need accuracy so I will be returning the E3 and look for something better. It's too bad cuz I liked the physical layout of the E3 and it was easy to wear at the gym.

Here is my terrible written and unorganized review of the E5.
The Creative Sound Blaster E5 is by far the best portable dac and amp I have ever used... Except for the fact that it breaks after a week of intense use. The software is useable and far better than I expected. The crystalizing and bass boost features are incredible. The E5 is very powerful and gets hot if left in your pocket. Its very bulky so using it with a 3.5mm male to male cable behind your phone makes it very large to put in your pocket or even hold. I don't particularly like the Bluetooth feature but ive never liked bluetooth for sound anyway. Bluetooths compression kills the audio quality.
I listen to music a greater part of the day and over the past month of using the E5 I'm not sure i can go back. Amazon accidentally sent me 2 of these (not complaining at all) and each of them lasted about a week before it would not connect to my computer or charge. Im currently on my 3rd after getting one replaced. My solution which im still testing is a magnetic wireless charging solution. It allows me to still be able to charge it (not very effectively but it works) and not wear the port out. After the micro usb port wears out, you are still able to use it until the battery dies.
I would absolutely love to give the E5 five stars but considering im on my 3rd one, its hard to give it even three stars.

I got this primarily to help amplify the signal from quiet movies when I'm watching on my phone.

What I ended up using it for went beyond that. It's a great drop-in for work where your computer there probably has really crappy sound circuitry.. IF your headphones could even reach down to wherever your computer is.

It's capable of some really impressive sound enhancement and more richness than I expected. I'm listening to it with my Shure SE215 in-ear headphones. As A DAC, it's really good. And this thing gets really loud. I'd probably get hearing damage listening to music on it at full volume. The scary part is it's easily possible to accidentally do just such a thing with its volume slider (be careful!). As for listening to quiet movies - it's great. There is a dynamic sound compressor for normal - light - and night modes that fixes all of that.

Now, as a standalone audio-jack-input device, it doesn't shine as much. It's still good though. You'd be best suited to adjust the EQ on your phone or whatever it's plugged into to adjust the sound. None of the DAC features work - no Crystalizer, no bass boost, no dynamic range compression, none of anything you'd see in the Sound Blaster control panel. You WILL get the added richness of sound that comes with the circuitry and the added volume from its built-in circuitry and amplifier.

The dual out headphone jack is perfect for those trips where you have one tablet and two people trying to listen. In standalone mode, it beats out those headphone jack splitters you'd pick up at Brookstone in the airport by a million to one.

Battery life seems to be great - I've never depleted it before remembering to plug it in for a charge every week or two.

The only thing I would change - at this price point - is for the E1 to somehow retain its last configuration when it was connected to a Mac/PC for use when it's a standalone amp. Even if I couldn't adjust those settings or turn them off, to have that capability would be amazing. It's the only thing I really wish it could do that it doesn't.