I'm a bit of a late-comer with this, but I JUST got Emperor's Tomb for Christmas, and so far it's not too bad. My all-time favorite game in this genre is "TR: The Last Revelation", so here's how I think ET stacks up against that one:
Graphics: ET WINS
The graphics in Emperor's Tomb are really impressive at times. The sense of height and space in the outdoor areas is something TR could never quite accomplish. Also, of course, TR had the limitation of right-angles everywhere, which severely hindered things (if you play around with the TR level editor a bit, you'll soon realize just how limiting this really is.)
Controls: TR WINS
Okay, yes, I can get used to ET's controls and they're not as horrific as I first thought, but that's hardly a compliment. The fact remains, I find the controls very twitchy at times, and I often feel like I'm fighting them to get Indy to go where I want him. In TR, the controls were far more cooperative.
Exploration/Puzzles: TR WINS
ET has small, very linear levels. This is okay (particularly since the designers made the bone-headed decision not to allow in-game saves), but I prefer TR's larger, less linear levels. I really felt like I could explore the levels in TR, whereas in ET, I feel like I am just working my way along a predetermined path. In TR, I was always finding hidden ledges, concealed paths, etc, etc. None of this really exists in ET, sadly. As for puzzles, I really haven't seen too many in ET, and the ones that do exist are painfully simple. TR has some really tricky, yet solvable-without-hints puzzles.
Music: ET WINS
Although TR had some great music, it was used far too sparingly. ET has good music throughout, so it wins.
Combat: ET WINS
The fist-fights are a lot more entertaining than the auto-target shootouts in TR. In ET, the fights are highlights. In TR they are often digressions.
Other Stuff: TR WINS
The lack of an in-game save in ET is incredibly annoying at times. It wouldn't be so bad if the controls were better, but it's infuriating to reach the end of a level and then die because the controls didn't do what you wanted, and have to restart the level. To make matters worse, the loading times in ET are awful.
So bottom line is, ET is good at times, infuriating at others. The sad thing is, with better controls and the ability to save anywhere, this could have been a excellent game. As it stands, it's an enjoyable enough diversion until something better comes along.