Never tried any of the sites above, but I did just go through a month with
www.dvdrentalcentral.com, which is basically the same thing ($20 month,
unlimited dvd rentals with up to 5 titles out at a time). I give them a
definite thumbs DOWN. Their catalog is pretty large but don't let that fool
you, from my experience very little of it is ever in stock. You have to
blindly compile a list and settle for whatever titles they happen to have in
on the day they process it. I had a list of about 35 movies and almost
always got movies at the bottom of my list(I hardly picked any new releases,
either). I would send back titles as soon as I watched them (1 or 2 at a
time) but they would somehow be "received" in groups and towards the end of
the month I wasn't even getting 5 titles shipped to me, I assume because
none of the titles on my list were in stock, but who knows because their
system doesn't tell you and their customer support is not very responsive.
Also, a couple of the DVDs I received skipped quite badly. Overall it was
like going to a buffett that advertises all this great food, but by the time
most people get there all that's left is cornbread and mac & cheese.
Basically, it comes down to the old (but true) adage that "you get what you
pay for". If you just want to watch something, anything, and aren't picky
then you can come out ahead. Otherwise I'd say it's better to just spend
the extra money (per unit, at least) to rent when and what you actually
want.