I don't know that brand, but I moved from 2 wheels to 4 wheels ages ago (Rimowa) and I find 4 wheels much more convenient. You might lose just a little internal space (2 more wheels clipping the corners) but when travelling through a crowded airport or station you take up less floor space, there is less opportunity for others to fall over your towed bag, and it's easier to kick the bag along when waiting in a queue.
I agree with all that and to me the key with a four wheel bag is that it rolls well. Not all of them are the same in that regard. A good rolling 4 wheel back is the way to go for me. The bag I mentioned above does well even on think carpet in the hotel and that is often a struggle for the cheaper four wheel bags.