My take and experience is that some SP take pleasure - some of the time. I like to give RO both because I enjoy it and because it often warms up the SP and she then is more likely to give a better performance. I use the word performance because even is she enjoys it somewhat or even a lot, it is still a performance with some faking sounds alongside the unmistakable sounds of pleasure.
Have had the odd experiences of SPs variously telling me I am a pro, asking what I would really like and querying with a smile on a second visit if I am in the market for a mistress ( she meant in the sense a regular rather than whips and chains). I think in each case it was either a quiet day or I was the first client of the day. In three cases, I went for a second visit and I was remembered and it was again good. The key indicator is whether they get turned on and actually want to fuck. One of the above engaged in deep penetration with her heels on my shoulders. In each case social time was good. Curiously most of these have been African or Latina and all engaged in social time. A chicken and egg whether good sex leads to good social time or the other way around.
But lest you think I am bragging, let me state that these examples are exceptional. At the other end, I had one experience of a SP, interrupt proceedings, telling me she was not in the right state of mind and give me my money back! With EE, I find them more mechanical and if I struggle to come tell me variously to take them in doggy or missionary as if there is one position that makes us come faster! When the SP does not enjoy RO, refuses fingers and uses lots of lube she is clearly trying to avoid taking pleasure. This is understandable as one my unforgetables reasonably pointed out, there is only so much pleasure they can take and too much wears them out and makes it more difficult to put in a long shift. This is obviously an issue for those in nonstop demand.
Comparing the two categories, another indicator of whether they can take place is age and experience on both sides. Best chance is with a SP with a few years experience but is still young, takes care of herself and is successful in pulling enough punters with a policy of providing good service to get repeat business. Best chance for a punter is if he is is in good shape, clean and respectful.