Went for "A friendly and welcoming personality" because it puts you both at ease from the off. All my best meets have started off this way, and looks like it's the leader in this poll.
If you've done your homework, SP will fit into your physical preference and offerings. If the profiles well written and honest it's a good indicator too.
TBH AW reviews are a minefield and I always read between the lines for UKP reviews. How often do you take an Amazon/Tripadvisor/Google review as 100% accurate? One man's meat etc. Particularly for things which are dependent on personal taste, like food/restaurants. To that extent that I'll often look at the reviewers other reviews. If their tastes align with mine I'll be more inclined to add weight to the review. Moreover, SPs can always have an off-day, or attitudes change with time; or even improve (let's face it, I wouldn't say it's an easy career and we all get better with practice, right?).
When you've made your decision and started the comms process, I have to think who's doing the comms? Sometimes it's hard to tell whether it's handled by a third party, which for me is a warning sign. I've also found that experienced SPs cut and paste replies if they're doing their own bookings, (if they're busy, it's a good sign!) which can come across as cold, but in person the opposite is true.
Really, having gone through all of the due diligence, what you can't get a handle on is whether the SP is doing this solely for the money and hates herself and you (which will likely be one of those regretful meetings) or whether there's an element of enthusiasm (acted or real), which you only get an indication of when you finally meet face to face. Personality goes a long way for me.