Admittedly, I like the art on the maps in Masters of the Elements more than any of the other Chronicles titles. There's something about walking around in elemental planes that just tickles my fancy, and I enjoy wandering around in cloudbanks or on a virtual ocean floor. Too bad the automap isn't bright enough to change its colours to match the world, but that's a terribly minor gripe.
The rest of the game is strictly standard Heroes fare. You've got the drawn/rendered look of the entire Heroes series, the clean interface, and graphics that, while detailed, haven't changed in a few years. The maps seem a little less packed with 'stuff' than some of the previous titles, but that's a relatively minor gripe.
Soundwise, Masters is identical to the other titles in the Heroes III line. The music's the same and the effects are the same. The voice-acting in the cutscenes is different, of course, but the game's not exactly loaded with that stuff. The music was fantastic when it first came out, but I've been hearing it in every Heroes game since, so I've taken to playing my own music while I play. It helps my sanity.