Alex-is it on par with Robuchon at the Mansion and Guy Savoy?
To me, the top three places in Las Vegas are Joël Robuchon, Guy Savoy, and Alex (in that order). I thought Joël Robuchon was significantly superior to Alex with respect to food, presentation, and service. However, expect to spend twice as much at Robuchon.
Guy Savoy was also excellent, but I didn't enjoy it quite as much as Robuchon. Alex was nearly as good as Guy Savoy, and is a relative bargain compared to the other two places.
I'm a big fan of L'Atelier - especially the tasting menu. Its food isn't as good as the above three places, but it's still very good indeed - I'd place it in the top five or six places in town. L'Atelier is very informal, and doesn't attempt to match the service or atmosphere of the other places discussed above. A big plus - it's much less expensive than the top three.
For lots of details, see my reviews at http://home.comcast.net/~lasvegasvaca... .
I've eaten at both Alex and L'Atelier. I thought the food at L'Atelier was more interesting and better prepared; we weren't crazy about the menu at Alex. However, we also weren't wild about Renoir, the previous venue for the chef. That said, Alex is a beautiful room, great service and very much more "upscale" than L'Atelier. We did enjoy the wine pairings at Alex, as well.
Price at Alex and L'Atelier should not be too much different. Food are great in both places. I guess you may also want to consider on what kind of eating atmosphere you want. L'Atelier is just besides the slot machines, it is kind of casual. On the other hand, Alex is quite formal.