Yeah, I've got two of these and they're OK although I have had some issues.
Does the bit on the back of the lock that fixes the rack to the bars have some ground edges on it? The first one I bought didn't have and if the rack moved ever so slightly when it was fitted, then the square edges of the locking part would get stuck against the lugs that poke down in the hole it passes through (hard to visualise but look at the parts & you'll understand).
You'd have to whack it back into a more central position with a hammer before it would release.
Once set-up and I had used mine a few times they were no bother. You need to release the wheels chocks and move them inboard. Then mount the bike into the clamp correctly & then set-up the wheel chocks. Once you have done this once for each bike then mounting them should be fairly easy to do again & you won't need to do the chocks each time. It does take a bit of forethought & knack though.
The other problem I had with mine were that sometimes the locking part of the clamp wouldn't lock. So you'd put your bike in, twist the grip & let the clamp spring up. Lock it & take the key out, then give it a pull to check it was tight and it would come undone - even in the locked position.
This now seems to happen very infrequently with the carrier set-up for my bike, but the carrier for my partners bike we had to send back as it did it pretty much all the time. The first time was in a rainy car park after a soaking wet ride & I spent about 20 mins trying to get it to lock. Then when it did lock, I stopped about every 2 miles to check it was still locked.
I would recommend getting a bungee cord for each carrier just in case you have the same issue. At least then you can clamp it up & then hold it tight with a wrapped around bungee. I use these now as a back up anyway.
I got mine from roofbox.co.uk & the lady I dealt with exchanged the faulty one with no qualms and sent the new one out within days so at least you shouldn't have any issues if there are problems.
Just keep the receipts.
