personally, i've always enjoyed adlard's interiors more than moore's. toni moore, though, did WAYYYYY better covers. when i went back and re-read the early issues, it struck me how different the artwork was, and i realized that while i like toni's interiors, i much prefer adlard's interiors. on the flip side, while i like adlard's covers, he has yet to match any of toni's covers (1-24), with the exception of maybe #36. #48 was nice, but toni already did that better with #6.
It's hard for me not to feel like Moore is "the man" on this book, if only since he was there from the start. It's probably not fair to feel that way, since Adlard has done so much more work on the series as a whole. I agree that Tony's covers are better overall, but Adlard has done a few covers that I love. I do love Adlard's interior work - so clearly I like them both.
From a collecting standpoint, I gravitate towards Moore sigs and sketches (only on books, I don't have full size Moore sketches in my collection,) and just don't feel the same pull with Adlard. I mean I do have several Adlard sigs and one zombie sketched book, but I don't feel that same drive to get ahold of his work that I do with Moore. I can't really explain why any more than to say - personal preference.