I own DVC now, but started my addiction by renting. (I'd love to camp Ft W again, but just can't drive that far)
I rented twice: Once the owning family was having difficulties paying their dues and the owner rented her points to me in exchange for paying them off for her. It was an odd transaction where I had to talk with member services (cc info for the dues) and I was afraid the owner might not follow though on my reservation. The woman was nice and honest from the start, she gave me her work location and phone to verify who she was. It all turned out to be a fantastic treat as I was used to staying in the Moderates (POR) and the DVC rooms all have the blessing of a balcony and kitchenette/kitchen. We stayed at OKW/BWV and Loved it! No problems checking in.
Second time around I rented from another person on the DIS, stayed at AKV/VWL. Again, no issues, LOVED it! Turned out to be the 1st week AKV Jambo villas was open - didn't know how lucky we were to grab a unit.
I've never had a chance to rent our points... I seem to always have just enough to survive on.

There are a lot of good owners out there who just need to rent out their points before they expire. But like with anything in life, there will be one bad one in a bunch of thousands giving the rest a bad reputation.
As I tell my kids: trust your instinct. You'll know if someone's giving off a bad vibe. Good luck! Where do you want to stay?