Sorry to hear you had a disappointing first experience. Service levels do vary quite a bit among MAs, all the way from just massage with an HJ to some subset of every acronym you can think of, including FS.
As a general rule, you shouldn't go in expecting kissing unless you've asked the girl in advance or if she advertises GFE. You might get it, you might not. GFE almost always includes some kissing, even though Tolleman's criterion doesn't require it for a GFE session. Note that GFE in the massage context means something totally different than GFE in the SP context.
Also, be aware that the rules at CMJ and Brass prevent BJs and FS. Yes, the odd girls do break the rules, especially with regulars, but you're generally going to be disappointed at those two places if you're looking for this kind of thing. (Some girls will do bareback pussyslides as a way to work around the rules, but my impression is that management is discouraging this lately because too many girls were getting sick, and it causes problems when clients also get sick.) Most other places in the city are much more lax on what is allowed, unofficially or quasi-unofficially, and at least CBJs are not uncommon.
Anyway, to answer your title question, the reason I prefer MAs is because I like the conversation, the skin-on-skin contact, and the long tease. (The convenience is also nice.) With SPs, I either worry about blowing too early, or I do blow too early and then have to caress this person I know very little about until I get hard again for round two, and at that point I'm not into it as much unless I'm really, really horny. Generally the conversation is a lot better with MAs because when you're lying on your front you've got a lot of time to talk, and the girls are often less jaded than SPs. And if you love bodyslides, it's harder to get nuru with SPs.
Health risks are not really a reason to see MAs over SPs though; I think MAs are riskier on average in that sense actually for a variety of reasons.