I raise potbellies for meat and they are awesome. People who have a bad experience with them have often taken an obese, older animal (and usually a boar at that) and yeah, you'll be disappointed if you do that.
But it's not about the breed. If you took a 5 yo boar of any breed who was so fat he had rolls over his shoulders, you'd fully expect it to be nasty - gristly and strong.
As far as not getting bacon - potbelly bacon is the loveliest, most scrumptious bacon I've ever had, and a big part of why they're my breed of choice. But again , if you have an obese animal .... anyone here read James Herriot? In one of his books he talks about how it was a point of pride on Yorkshire farms to have the Fattest Pig Possible and his disgust at being served a slice of bacon "endless fat with the tiniest strip of pink barely visible". Obesity doesn't make for good meat.
If you want good (and I mean like really, REALLY good) pork, go get a couple of those cheap potbelly piglets and put them out in a nice big pasture or let them free range the barnyard. Then plant an extra row in the garden for them, give them all the good hay they want, lots of fresh veg and just a handful or so of grain. They are pigs that were bred to gain on a high-fiber diet and I've raised good ones who got most of their feed just from pasture, cleaning up after the other livestock and the literal handful each for a treat to put them to bed at night. You want them just a shade plumper than nicely muscled.
If you put them in a little pen and pour grain to them, they will get obese and of course the meat will be full of fat - they're fat!!
If you treat them like the world's cheapest Kunekune, you'll be delighted with your lovely, small, affordable, lard-type pig.
Oh, and about that 5 year old boar you got for 10 bucks at the auction? Have the vet out to cut him, worm him, put him on a diet, make sure he gets to run around and in a few months, he'll be just fine - probably the nicest hams you've ever had.