I played a few hundred different games so far (I'm loading the list alphabetically using Tafoid's MAMELOAD front end) No crashes and everything is playing great so far.
One thing I have noticed though is I have created a hbmame.ini *hbmame -cc* and it has HLSL settings in DIRECT3D POST-PROCESSING OPTIONS however when I set hlsl_enable 1 nothing happens in hbmame.
I'm unsure if this is intended behavior or not, but I thought I'd report it because it's the only thing I have noticed thus far.
[EDIT] After looking at my notes there doesn't seem to be any way to coin up and start the 4 different Alpaca games.