My experience parallels maddmaxx's advice.

When I got new 1600g handbuilts for my bike, the whole thing felt completely different. Handling and acceleration both felt lighter and the ride feels about as silky as you can get on an aluminum bike. Shopping for bikes earlier this month, I had it weighed at the LBS. 26.5 pounds with rack and lights, but without fenders, waterbottles and seatbag. I'd have guessed 21 or 22.

The new bike (still on layaway) tips the scales at 23.1 pounds (with fenders but without rack, lights, bottles or cages), but felt heavier, probably due to hefty hoops to support the trendy-looking low-spoke count and certainly because of the disk brake rotors. It also handles slower due to longer wheelbase and chainstays.

It's amazing to me that (until I shoulder it) the heavier bike feels lighter. It made the case for me that overall weight isn't everything. Wheel weight makes a world of difference, as does geometry.

Oh, and back on topic...

Arrange for the Kestrel to be fitted, then take a long test ride over familiar terrain--at least an hour, but two are better. If the LBS isn't cool with that, find one that is. Only then you can really tell how you'll like it. If you like it, buy it and don't worry about what anyone else thinks. If you don't care for it, you'll have saved nearly two grand.

Of course when I followed this advice myself recently, the bike I bought was $500 more than the one I originally looked at...