So, in watching The Early Days DVD, I have found an easy way to articulate why I slightly prefer Clive to Nicko. During the Beast Over Hammersmith show, you can really hear Clive propelling the music forward with intensity. Then the next show with Nicko doesn't have that same feel - Nicko has a more lay-it-back, Bonham-esque thing going which I don't like quite as much. Nicko's still great though.