Some general things to keep in mind:
1. You are paying for the escort's time. What you do during that time is by mutual agreement. She might have sex with you, she might not. Each girl sets the fee she wishes to collect for her time. Some charge by the hour, some by the date, some by the night, etc. (although by the hour is the most common).
2. How much you pay has little bearing whatsoever on the kind of experience you will have. That is, you can pay $100 and have a fantastic time with someone, or you can pay $5000 with someone and have a lousy time. It doesn't matter whether the girl is a porn star or not.
3. How much you pay for her time has absolutely no bearing on how attractive she is, whether or not she's drunk, high on drugs or anything else. There are porn stars who are alcoholics, meth heads, etc. just like streetwalkers. There are some that are fit, there are some that are not so fit. And none of this has any bearing whatsoever on the time you will have with her, unless she physically repulses you. That is, you can have a fantastic time with a pudgy/fat drunk/high woman just as easily as a fit, sober woman... as long as you don't mind that she's not fit or not sober. Some people are turned on by overweight girls or drunks or druggies or ...
4. If sexual activity happens, the price you paid, the looks of the girl, the fact that she is or is not a porn star, is or is not a drug addict, has very little bearing on what sexual activities she will do with you. Some girls allow anal, some do not. Some will give blow jobs, some will not. Some will try and get you off as quickly as possible so you're out the door as quickly as possible and some will do multiple activities, multiple positions, and even multiple orgasms. Each girl decides what activities she will do with you.
5. Some girls will insist on a condom. Some don't won't. Some will ask for tests, some won't. Each girl has her own rules, requirements and restrictions. It doesn't matter whether she is a porn star or not and porn stars are no more likely, nor any less likely to require condoms as non porn stars.
6. Yes, in some cases, extra dough will get extra activities. And, yes, sometimes extra dough will get condom-free fun. Frankly, these women should be avoided.
7. Reviews are VERY useful for helping you decide whether or not to spend the money to see a particular escort - porn star or not. But, just because someone else had a good (or bad) time with a particular escort may have nothing to do with whether or not you will have a good (or bad) time with the same escort. Sometimes it's a matter of chemistry, or maybe the escort wasn't feeling well, or there was some reason why she didn't like you. In any event, you should not rely on a single review to tell you what kind of experience you will have - each individual's experience with each individual escort will vary. Reviews serve as a guide to help you make your decision and are not to be read as a definite guarantee.
Of course, all of this is just my opinion... formed after many years of hobbying. Your experiences may vary.