While Horner obviously knows what he's talking about, and surely isn't doing a bad job, to my ear, he exudes this forced intensity that makes him kinda hard to watch and listen to, like he's always in competition to get some (more) speaking time in (which may well be the case, but I shouldn't be getting a sense of that). It's like someone needs to take him aside and tell him to just slow down and relax a little.
Also, his squeaky,cartoon-character voice is a bit tough on the ears. All MHO, worth what you paid for it.