Runes of Magic US / AU

what these players are selling is the stat from gear bought with mems.

They pretty much say "hey, I am about to pull the stat, do you want to buy what I get sight unseen". If they get a good stat, you get a bargain and pay too little for what you get. If a bad one, you pay too much.

Be careful when doing this and make them link the item before they stone. They might have gotten a nice OD item that you would want to unbind instead of stone, albeit at extra fee. Or they might have a bad stat from previous pull that that they would want to palm on you even if they pulled a good one this time.

I agree with wiffo on this. Renting mems has its downside. Always do so at your own risk. If you decide to do this I would recommend you go with the person to where they will be getting the gear, and have them link it when they get it. Like wiffo said that way you may be able to get a nice pice of gear instead of just a stat.

They can pull the old "switch-a-roo" and have a poorly stated item already in their bag which they'll sell to you :-(
You're much better off getting/earning your own mems and doing the turn in yourself

IMHO, worth only if you gonna buy someting with already known stat. Otherwise you can get screwed like vfwiffo mentioned before. I still rather buy stat from AH... you know what you will get.