I have been using this for two years. The size is okay for short trips. I could not fit my 15 laptop in there. The plastic holder across in the front of the bag makes it difficult to fit some items in. I thought it might rip at some point, but it has not.
I wish the handle had two bars. You cannot rest, for example, your laptop bag or purse on the top because it will fall off while you are walking really fast trying to get to a completely different terminal after your plane moved. That makes it quite annoying.
I have not been able to slide it under the seat in front of me, but I never have an issue with it fitting in the overhead bins.