We just did both of these for the first time a few weeks ago. We enjoyed both restaurants, but honestly, we're not in a hurry to return to Space 220 again. It wasn't terrible by any means, everyone enjoyed their food, but for the price you pay I would expect them to be able to properly cook a steak to temperature and not one that was ordered out of our group was correct, they were all over. Conversely, our daughter got the children's salmon and it bordered on being undercooked, though it was still safe. I seriously debated sending mine back but I didn't want to be waiting for food and be the last one eating and holding everyone else up so I, and everyone else impacted, just dealt with it though we made certain that the waiter knew for whatever it was worth.
Le Cellier was actually very good. I have always wanted to try it but after it started getting negative reviews when it became a signature we always talked ourselves out of it. This time, since we were not on any sort of meal plan and it wasn't that much more expensive than other options we decided to give it a shot. We really enjoyed the meal and unlike Space 220 everything was cooked properly. The cheese soup, pretzel bread, steak, crème brulee were all fantastic and while the service was good at both places, I felt that the waiter at Le Cellier was just a little more personable and really shared some of the history of the restaurant with us.
If you are set on trying both I would try to get the Space 220 lounge reservation as the cocktails are good and fun, and this coming from someone who generally just drinks straight whiskey. And all of the appetizers were great. If we were going again with a group that was adamant about trying Space 220 this would be the compromise DW, DD, and I would try for.
