I'd agree with that. Facebook (for me anyhow) is nice for local stuff. But I don't trust someone from Facebook to ship the way I would from a forum with some itrader ratings.
I also agree that rctech has a more active marketplace but I did get a decent deal recently on a 1/18 axial here. You never know what you'll find and where.

​​​​​​Even reddit has an rc marketplace now. I haven't bought anything there yet. I don't see any feedback going on, that makes it tough.