I also live about 20 minutes away from the TRex Cafe in Kansas City. We went last February and it's been open for a couple of years now at least. We went at about 3pm and had almost a 2 hour wait for a table. Very busy, very noisy, very crowded, and very expensive. While you wait, they have a ton of expensive activities to keep the kids busy, as well as a pricy gift shop. There is a build-a-dino area tied in with Build-A-Bear, a place where you pay extra to go do a "dino dig" and dig around in pebbles for buried plastic bones to make a mini-dino that you can then bring home (or you can buy the same kit in the shop for 1/3 of the price), and there is an area with computer games and a "cave maze", also for extra admission. The line for this stuff was pretty long. They had a photographer walking around taking pictures, then they stick a border on it and try to sell you the photo for about $10 - very similar to several WDW character meals, but minus the characters. I have pictures but am too tired to find them right now. I'll try to post them another day.
The food was excellent, we all liked it a lot more than RFC (we have one of those in our mall) but it was pretty overpriced for what you get. Desserts were huge and had fun dino-themed names. Similar to RFC's "tropical storm", the TRex Cafe has a "meteor shower" every 20 minutes or so - loud, dark and scary for little kids.
It's a fun place, but definitely a wallet-buster, much more so than RFC. The place is absolutely HUGE, it's 2 stories and each room has a different theme. It's beautiful, well themed, and lots of fun. But it is very loud and hectic, and can be scary for some kids. Mine loved it and can't wait to go back, but I'm in no hurry. I imagine the DTD one will be similar, if not bigger, than the KC one. I heard it's slated to open in 2009.