Do not be afraid to deal with any of the site supporters advertising on the site. They are top notch individuals or they would not last here a day.
As far as dealing with other site members, yes you are taking a small risk. My advice would be, if you see an item for sale by another site member make note of their name and search for them in the feedback section. If they are a long time member with good standing then contact them and make an offer. I have dealt a few times with other members and each time was a smooth, honest transaction.
If your unsure about a dealer advertising on the site, they have feedback threads as well. Good luck!
Quib