Old Kia's (pre 2000's), yes, not great cars. The one you are looking at looks like a great deal. I'm a fan of keeping older cars running but there is a bit of a dimnishing return after 200k (IMO). Also, reliability needs play in to it. If you use it once a week to go 5 miles is one thing, relying on it for work and/or travel means that a failure on the road isn't really acceptable (unless you are just one of those people who is wired for adventure).
As you noted sometimes the rebuilt alternators aren't necessarily great. I've heard stories of the companies basically blasting and painting them, taking components out of a bin that are servicable, throwing them together and reselling them. So could fail in an hour, a year or who knows. On most cars, getting to the alternator is such a hassle I'd spring for the quality new / rebuilt item every time. I've had this problem with alternators, water pumps, and brake components that have been reman'd.