Well, I said I would not do it again, but I just could not help myself! I did this club several years ago, fulfilled my obligation and quit. Everything previous poster said is true - however, you CAN set it up so that you can reply online if you do or don't want the movie. This is better for me than trying to remember to mail a postcard.
Overall, you pay less per movie, it's just waiting for the good deals - and I bought the 2 extra movies at discounted prices, so I only have 2 more to buy, I think.
The selection is pretty good (go online - there are TONS of movies listed there. Lots of oldies too, if that interests you). We had not completely replaced videos with DVDs, so it was a cheaper way for me to do this.