I got my 1/2hp Cabela's Commercial Grade off craiglist for about 1/2 shelf price. Left to my own devices, I'd have gotten something in a #12 instead of the #8 I have, only because the size of the chute is the only limiting factor. I can't physically shove enough meat into that chute to slow down the grinder. I would probably be a little happier with a #12, but honestly, when I did the grinding for my buck, I had a total of nearly 50lbs of grind, done in two sessions (because I trimmed the meat from the deer in two sessions), and it took some time to work through it all, but the end product is very good.
My wife is very picky, and she's very pleased with the end results from the grinder.
It's not a small investment, but if you're committed to self-processing deer, I agree it's worth it in the long run. One benefit of the higher-grade grinders is that you can add attachments later if desired. For example, I can see buying a mixer attachment for mine, which helps mix batches of ground meat with seasoning/cure for sausage, snack sticks, etc.
I have taken deer to a very, very good butcher, and the last deer I took there was in 2013 and my cost for one deer was $165 and that's probably lower than many in the area for similar work.
The complement to the grinder that I highly recommend is a FoodSaver or similar vacuum sealer. When I grind, I put my family to work. I'm grinding, my 11yr old is weighing it into 1lb portions, and my wife is bagging/labeling/sealing it. We can power through a deer in no time.