His glazes are okay. It's his illustrated, appliqued, or free form pots that are the standouts (and mostly unaffordable and unavailable).
Haha, his glazes are just okay? I agree that not all of his pots are standouts, but I really love the blue/green glazes or the white glazes with hints of purple or blue peeking through. They are just showy enough, but very usable in many tree pairings. Some potters' glazes look amazing on display pots, but are tough to match with trees (or at least they would be for a amateur like me). Lenz pots straddle the line very well. Of course this is only my opinion and I respect differing opinions.
I'm about due for a trip to the Arboretum, so I'll see if I can get a behind the scenes peek. The pots you describe would be really neat to see in person. I think more than anything I just respect what he's done for bonsai in America. I feel like owning his pots is like owning a little piece of American bonsai history.
BTW, is that blue cascade pot you posted yours?