Well, from what I've seen, they both have some similar philosophies - I haven't looked too deeply at TempleOS's code, but I remember hearing Terry say some concerning things in his interviews about scope and encapsulation, etc. Terry largely has a philosophy of not wanting to be saved from himself, which I can respect, but it came off to me like he's the kind of guy who'd make everything globally accessible, which would make it a nightmare to work with. That's something he and Thor have in common, actually.
I'm not bashing Terry as a person, necessarily, but I've always gotten the sense that Terry is sort of an outsider artist as far as code goes, and I feel the need to assert that volume of effort and quality of effort are not inextricable. There can be a lot of something, but that doesn't imply that any of it is good, necessarily. The sheer amount of what he accomplished is impressive, sure, but that doesn't necessarily imply he did it in an especially-skillful way, and I see a bunch of people saying that because he built TOS on his own, that he must necessarily write good-quality code in doing it, when that's not necessarily true.
That said, that's also not me saying he's definitely a bad coder, just that I can't guarantee he's a particularly good one. If any of you guys have actually done a dive on Terry's code and I'm way off-base, though, by all means, put me in my place.