I leased exactly once -- when I went HD and needed a new dish (1000.2 WA). Up until then I had owned and installed a single tuner/LNB receiver (3700?), a DVR 508, a Dish 500, a DVR 721. All my purchased receivers have been bought through Mark at Dish Depot.
Then Dish obsoleted the 721 and sent me DVR 522 to replace it (and read me a long spiel on the phone saying the replacement was a lease which turned out not to be the case). The first 522 I received had a faulty tuner 2, not sure how that made it out of QC. The second had scrambled sound after about 5-10 minutes on the same program. The third worked as far as I could tell, but I was already turned off to the quality of refurbs from Dish.
By early 2009 when my SD TV went TU for the second time in 6 months, I decided to go HD. Dish offered a free install. The installer, a contractor, did a great job installing the new 1000.2 (two RG6 coax from the dish to a grounding block), and running a single RG6 cable for the new DVR 722 (was going to give me a 622 until I requested the 722). When he went to leave he asked me what I wanted to do with the 522 since it showed as owned on his worksheet. Hmm, news to me. I think he gave me $10 trade-in for it and took it with him.
So the 722 was leased and all was well, until... It started acting wonky (freezes, reboots, etc. all known symptoms of a hard drive failing) about 4 years later, I decided to upgrade to a Hopper system. I probably could have fixed the 722 with only a compatible drive swap but couldn't (technically) because it was leased. Or I could have tried to get a functional refurbed 722 but didn't want to chance another possibly faulty Dish refurb.
Looking at my system and using information from Satelliteguys, I found all I had to do to hook a Hopper up was replace the existing ground block with a Solo Node, connect the 2 existing coaxes from the dish to the node, and connect the existing coax that used to go to the 722 to the node Host port.
So I ordered a Hopper with Sling with Solo Node in March of this year from Dish Depot ($199) and did the install (really just replacement) myself. I also bought a Joey in case I ever wanted to add a viewing room to the system in the future but so far haven't activated it.
Sorry for being so long winded, but the point I'm trying to make is that if you are the least bit handy, owning is probably the preferred way to have a Dish system (at least it is for me) since you can do fixes much more efficiently than through the Dish repair cycle. Add to that the other advantages people before me have listed. One last caveat -- once past the infant mortality period, the hard drive is the most likely component to fail on these units. If you decide to go this route, be sure to stockpile a replacement hard drive before it becomes unavailable for purchase. The HD used in my HWS is a Seagate ST2000VM003.