I believe that you'll save time and money taking a taxi. You'll likely save a little money taking Paradise, but you'll likely save a little time going through the tunnel in route to downtown.
I have eaten at Andiamo Steakhouse at the D, and it's downright outstanding. It's an Italian steakhouse, which is a nice twist. You'll find great service, great find, and a nice atmosphere. While expensive, comparable places on the strip will run you 40% more. Like many top notch steak houses, the sides and appetizers are very large and quite reasonably priced. I'm guessing you'll get out for $80 a head. PJ on this site recommended this restaurant to me and it was good advice.