I got my Arkel Utility Baskets back in 2004. I do like them very much. They hold alot.
I noticed they have redesigned them since I bought mine. They now have a cinch/buckle type arrangement to compress them which is in my opinion probably an improvement over mine, at least for general purposes.
Mine are made with a draw cord type cinching arrangement which laces up the sides, and snugs the bag against the contents. With mine you have to be careful that the excess cord is under control cord and tucked away or it may flop around and possibly get tangled in the wheel etc. This is not an issue when they are loaded up, as the slack is taken up by the fullness of the load. It's when they are empty that it becomes an issue. Its quite manageable, just requires the brains to be turned on is all. The newer version I believe would eliminate this issue.
I also have the Arkel Trunk Bag, which I love.
I have not seen any of their other Panniers etc in person, but the ones mentioned above that I have purchased are very well designed and very well made.
They are not inexpensive.