My advice to anyone thinking of SA is to set up a free profile on the site, then do a search for ladies in the area that interests you. If you do think SA is for you don't subscribe immediately (unless you really want to), wait 3-4 weeks as you will receive an email from SA with an introductory offer to get a month's membership with a 33% discount. Once you get paid membership get in touch with Admin and access the thread on UKP, it will prove invaluable in the long term.
As Borat, robbie54321 and others have said, it's time consuming and you have to wade through an awful lot of shit to find those hot girls. But when you meet those genuine girls you will not find better paid sex anywhere! Last year I hooked up with what appeared to be a 7/10 English 19 year old based on her profile photo. In fact she was an 8/10 (genuine English 19 year old, size 8, 5' 6" tall, very long brown hair, great legs, extremely cute) who on our first date was happy to passionately french kiss, rim me, swallow my cum, do anal, for 3 hours (1 hour having a coffee in the hotel lobby, 2 hours in the hotel room). Costs:
Hotel - £59
Coffee - £10
Girl's allowance - £150
Total £229 for the best sex I had last year. Saw her 4 times last year before she decided to quit (these girls don't think of themselves as prossies but we know better!), but it's only a matter of time before she needs more cash and will get in touch with me.
SA works well for me despite being a married guy. But I would advise caution to any attached guys wanting to get involved because of the time and effort required to make it work for you.