One aspect as yet unmentioned.I'm primarily going down the SB route because of the $$ saved.
I just got home from a 5 hour date, which was $450 (including cost of lunch). She looks similar to Cindy from JG (check my posts for my review on her), basically curvy hourglass with natural DDDs. Lunch was 1.5 hours and play was 3.5 hours, which is basically how I would've spent 5 hours with an SP anyways. Except.. 5 hours from JG is $1000 (without food).
As far as sex goes, BBBJ was decent, DFK was good and everything else was great. Experience was similar to meeting a new SP to the industry, except with more intimacy since emotion is on the table as well.
Maybe I got lucky for my first date but if all the other girls are like this, SB is a very viable option for me...
NOTE: While I did save $$, I had to instead spend a lot of time texting back and forth, meeting for coffee first, etc. In the end, I think it was worth it though.
With an SP as long as you are not a total dickhead and you are fairly clean you are pretty much guaranteed to have sex.
There is definitely more uncertainty in that regard when it comes to first meeting a SB. You have to be a bit more on your game as she is checking you out. As such there is more excitement built up because of the anticipation/uncertainty. There is a bit more satisfaction in knowing you passed whatever her screening process is. A little more like going on a real date.