Haven't tried out MaLa in a while, but there was some reason I didn't stick with it. GameEx was a total bastard, initially. Then I got it to work, but for VP, as well as what I'd consider a programming issue with how GE makes a game list in Daphne. Multiple posts to the GE board, few to no responses. Someone figured out Daphne, but, really, should I have to do a work-around cos GE isn't making it's listing right? I still haven't gotten off ---my bottom--- and done it. I never got VP working.
Atomic was mostly golden...till it started displaying in French, out of the blue. Then some other issues. Fixed 'em - not sure how - and then they came back!...with no warning. Ditched that.
I fancy Mame32, cos it's the most stable, as well as giving you many set-up options from the UI. I'm currently thinking of a different skin concept for it, but how it works (except for a couple/few, very minor tweaks function tweaks) seems the best. Of course, I don't care about a lot of these esoteric options, like LED support, etc.