One of the main differences between the two is a "feel" thing. The way Eric plays drums, it's very Bonham-esque in that his count JUST behind the actual count. Some refer to this as playing on the backbeat, but as this is hard to describe, think of it this way: Eric stays in time, but his attack on each beat makes it JUST in time. You almost think he's gonna miss the beat, but he hits it as late as possible. This creates a unique, groovy pocket. Other drummers, say Matt Sorum for example, are more straight forward and robotic, and someone like Luzier almost PUSHES the beat. He is on top of it, and almost drives the song.
I can understand people who like Luzier, and in a way, I do too. I am a musician, and sometimes it's fun to listen to someone who is so technically talented. For that reason, sometimes it's kind of fun to see a clip of Malmsteen playing guitar, but it would grow old very quickly. The sudden bursts of Luzier's playing, like the solo in "Goodbye", for example, give me goosebumps. The DeLeo's actually coaxed him to play like that in that section, and I think it worked.
On the other hand, Kretz kind of writes 'riffs' with his drums. Much like Dave Grohl did on the album he drummed for Queens of the Stone Age, Kretz's patterns, grooves, and fills are 'catchy', much like a guitar part or vocal part can be. In that way, not only does he create a booming, laid-back groove, he also writes parts that are memorable.
Oh, and I am a huge sucker for Kretz's semi-open hi-hat that is just a bit too high in the mix. I used to argue with a friend of mine who is a great drummer--he hated Kretz's hi-hat, but I thought it was part of what made him unique--that almost out of time count so high in the mix, and just a little bit breath-y with that semi-open feel.
Of course that's just my opinion, I could be wrong.
