Make sure they are getting a great deal and find ways to assure them they won't be wasting their time or taken advantage of.

Of course you should have a quality product and it must sell (and be tested)
Sounds like you've been on the wrong end of JV deals before...

Well, I'm just about to find out whether I've got a quality product or not, and whether it sells... Google Adwords is just about to help itself to part of my bank account :'( ;D

The products are PDF guidebooks (Wedding Planning; Fly Fishing; Puppy Training; and Orchid Growing, respectively)... they've got bonus products with them, plus updates and unadvertised bonuses for the customer, but whether such PDF guides cut it these days, lucifer knows.