Arnie, I just finished an Avistar, my second. I had so much fun with the first I had to have another. Converted it to a taildragger and put a larger engine in it. That being said, I recently bought the Escapade and as soon as I have pending projects complete (GP Spectra E, I'm almost done), I'm going to start the Escapade.
So according to my thinking, get both. The Escapade is a much better "looker". Both I'm sure both are going to be fun. From what has been reported, I think the Escapade is going to be what I would describe as "hotter". If you've read this forum up to here, you know there are issues to check. But I think those isolated problems are pretty neat and completely workable . A lot of the guys ahead of us who have flown the Escapade have shared so much, and are to be commended for what they have reported.
From what I can tell, the Futaba S3004 is a small upgrade over the S3003. They both have nylon gears. They would be absolutely fine in the Escapade but if you've stripped out an S3003, you could consider a gear rebuild. It's actually pretty easy with the new gears set. I'm more familiar with Hitec and am putting HS-475HB Super Pro BB in mine. But I think the Futaba's you describe would be fine. Start studying servos (Servo City is a great place to do this
http://www.servocity.com/index.html) and you start to get a good feel for what might work for you. Cost, speed, gear material, weight, torque, bearing type, gear type, all are things you can consider.
Sorry to hear your Avistar bit the dust, I really liked my first and brought it back to life many times.