I really enjoy low/mid-low cap that you get with GBBs, having to worry about your current mag capacity, or even organising partially used mags within your rig is an additional level of the game if you're into it, and in fights, for CQB at least you're not really at a meaningful disadvantage, what I really dislike however, is that you end up spending a lot more time in the respawn topping up every mag / gas in order to go back out fully loaded, versus if you just had an AEG where you rarely even have to top up in-between lives.