Didn't care for Harrison at all until INDIAN BLUES on Candid. That was an album that had a little different flavor to it at many different levels. Still can't call him anything close to a "favorite" or anything, but that album seems to have been a turning point for him (or at least a documentation of same). He seems to keep growing, so hey, it's all good.
As for Locke's endorsement pic, well, I can show you a King ad from the very early 1970s with images of Cannonball Adderley. James Moody, & Rahsaan Roland Kirk. Also Pharoah Sanders & Paul Gonsalves endorsing Otto Link mouthpieces. Sonny Rollins doing the same for Guy Hawkins mouthpieces (that one didn't last...), and on and on and on. As a player, Locke neither excites nor offends me too much one way or the other, but I'd not reach that conclusion just because he endorses a product that he actually uses. Endorsement deals usually carry a lot of practical perks in terms of free gear, supplies, repairs, etc., even clinician gigs (that pay REAL money!!!! ), so if you're a working musician, an honest endorsement deal ain't a bad thing. Hell, if you're using the damn stuff anyway, why not get it for free?