just to get you started...
The 501 PVR had a 40gb drive
The 508 PVR had an 80 gb drive
The 510 PVR had a 120gb drive, as I reacall.
All have essentially identical guts, features, firmware, and differ only by the size of their hard drive.
The
first two were grandfathered with
out the $5 monthly DVR fee.
Whether you can still get that deal on a new account or not, others will have to comment.
If I'm not mistaken (and someone will correct me) none of the newer, larger, sleeker units are fee-free.
And then there's the complication of dual tuner units charging you two DVR fees unless you plug in the phone line (reduces it to one charge).
I chose 508's a few years ago, and bought mine.
It was the right decision
then.
I stand by that choice and haven't changed my mind.
They have a limited useful life, and are getting along.
Older 501's have been around longer, may be in worse shape, and often suffered from a bad front-end chip which needed replacement.
(the 508's and 510's did not have a problem)
If and only if you could get new 508's today from somewhere like DishStore, would I recommend going that way.
And that is the only potential way to avoid the &$%# extra DVD fee they invented.
(to be clear: I'm against the 501's and 510's , as described above)
Now you're looking at what? A 625 for standard definition ?
Two good places to look if you are buying, are
DishStore and
Sadoun.
Both advertize here, support this forum, and I've dealt happily with both.
As to the lease-or-buy question... it's pretty much a flip of the coin.
Others will post their opinions and reasons, and both sides of the argument are valid.
I think the decision to get a service policy is probably a more serious consideration.
And that should be based on feedback you read here on the reliability of whatever receiver you choose.
Nobody services Dish receivers (nobody I'd much trust), so that's a consideration.