Flushed the power steering and refilled with Valvoline Dex/Merc ATF. I did this service 80K miles ago and noted then how kind of brown and greasy the fluid was, which I assume was b/c someone topped it off with something that didn't belong in there. Steering performance was much better but I don't think I got it all out last time so today I removed and cleaned the reservoir (which was actually pretty clean) and did a very thorough flush. Fluid is clear and red, steering is excellent, so I'll just keep an eye on it to be sure it stays that way.
Side note: I've done this twice and made a mess twice, each time in different ways.
Looking forward to 300K miles to see if the third time is the charm.