I live in Aiken, and I’d be happy to answer your questions.
On property taxes: There are city taxes on top of county taxes, but you are unlikely to run into that problem if you are buying horse property (though if you have deep-ish pockets and want to keep horses on tiny bits of land (with places to ride), you can buy a horse place within city limits.
Aiken County charges 4% of assessed value on primary residences, and 6% on secondary ones. Do your homework before interpreting anyone’s tax bill. I don’t recall whether the percentage being paid on a given parcel is listed on the Assessor’s website.
I believe there are surgical suites at the two big practices here-- Southern Equine founded by Jamie Carter, and Performance Equine which does a lot of therio. But the problem is keeping board-certified surgeons here. I’m not sure there is quite enough work to pay their specialized salaries, but I could be wrong about that.
Otherwise, you will find good, competent vets. I think the same is true for farriers, though I had my horse shod at Cornell by a world-class guy for a long time, so my perceptions of what counts as a good or great farrier have been screwed up. I believe there is a guy from Rood and Riddle in KY that comes to Aiken on a schedule. I believe Rood and Riddle is the last/only vet practice in the US to keep a farrier on staff. So if you want/need a $650 shoeing job here, that can be had.
OP, I hear you and see you and feel you about the PTSD of keeping horses in sh!te markets. It sucks the joy out of even owning them when you can’t protect them. That’s one of the reasons I moved to Aiken. And I moved to Aiken with relatively shallow pockets, given my taste in horse expertise. I grew up on the SF Bay Area and had lived for a time in the NY/CT corner of the world, so I had enjoyed the benefits of high-end markets… where I could never afford real estate. Aiken was a very good compromise for me, though the costs are escalating now.
Feel free to ask me more questions if you’d like.