I left the rear suction cup stuck to the glass on my Tesla 3 for about 2 weeks, and could not get it off. After buying a plastic scraping tool from the hardware store I was finally able to remove it after 30 minutes or so of prying and scraping. The rubber ended up fusing to the glass (in the pattern of a bulls-eye) which I'll have to remove with some kind of solvent.

Not lowering the rating, because the instructions say to stick it on metal, not glass. Just warning my fellow Tesla owners to avoid.

Original review follows...

Good but not necessarily great product but that's fine given the overall cost.

Suction cups were a little fiddly. One of them kept losing pressure, but I think I've got that fixed after thoroughly cleaning it. I'm also a little concerned about the long-term durability of the 12mm plastic adapters I bought.

But overall, I'm pretty happy with the purchase. It's holding my bike steady at near-highway speeds, so it's doing what I need.

2005 Honda Accord with a modern full suspension 29er all-mountain style MTB.

Short drives to the trails thus far without issue. A little nerve racking seeing your bike lean on turns but none of the suction cups have lost force nor has the rear wheel strap felt insecure. I'm worrying less and less the more I use it and the more I figure out the proper flow of installing.

The only thing I don't like is that the suction cups leave visible rings on my paint that have not yet come up with general wiping and washing. I don't care too much with my older vehicle but I would be hesitant to put this onto a newer, nicer, more expensive, or specially painted car.

*Update*
Left my bike on my car after coming home from the trail for 3 hours and there was noticeable loss of vacuum from all 5 suction cups. The white band was nearly showing in all 5 so it may be best practice to check and re-pressurize every 2 hours or so on longer drives.

I procrastinated like crazy and received this mount the day before doing a 1200 mile road trip. With nothing other than a youtube video's instruction this mount made it the entire way with no issues whatsoever! I am immensely impressed with this product!

The skewer certainly could be better.
I've used this a few times. Last time just before getting home sounded like something was rattling up top. Turned out the skewer was loose. Only the lawyer lips on the fork kept it from falling off.
It's probably important to make sure all parts are properly aligned. The plastic part on the lever side of the skewer would be an easy one to get wrong, and is my #1 suspect.
But the nut at the end of the skewer appears to be plastic (it's certainly non-magnetic) so I suspect it could jump a thread or two under pressure.
I've uploaded photos; first three are of the original skewer parts, last one is a picture of a Shimano skewer end nut showing its metal threads.
For the moment I've borrowed the skewer from a Shimano RS-31 wheelset I've got in storage. I've ordered a new metal threaded end nut for the Rockbros skewer; they aren't so cheap ($10). Order a nice cblack Shimano skewer, expect to pay much more.

Good: Unit arrived we'll packaged. Suction cups come with protectors. Rear wheel Velcro strap is descent. Suctions are powerful. Bike never touched the car.

Known flaw at time of purchase: Only fits old axles. If you have a newish MTB bike with the 15mm axle, you need to order a separate fork mount and alter to fit new mount. ($20). This took a few minutes but I knew that going in.

Meh: Aluminum brace flex's when testing the strength of the unit by pulling slightly on the bars. Not a big deal. Sufficiently supports bike but could be stronger. This also allows you to mount it to a curved surface so I guess it's a trade off. Doesn't supply a way to secure the pedals/crank so they don't spin and hit the roof. Extra Velcro would have been nice.

Bad: No washers used in construction to spread the load. Suggest adding quarter sized washers if concerned. Imo the hardware would fail before the suction cups.

No release valve. Only way to get these things off is to lift an edge and break the seal. Not a big deal if mounting to glass, but would be careful if mounted to paint.

Process: Put bike on fork mount while on the ground with protectors on. Secure axle. Lift bike and unit to car while removing protectors. Suction all cups. Lift rear tire and place rear tire cup. Strap rear tire. Done. At destination remove bike by breaking the seal on all cups and dismounting bike. Place unit in trunk.

Overall: Legit cool way to transport a bike. No cables, hitch, vehicle alterations etc to mess with. Very low chance of vehicle damage if you are careful. Takes a couple mins tops to get on and off. 1/2 price of the 'name brand' one. Well worth your money.