I'll throw out my opinion, but seeing as how the frameset you were looking at on eBay is going to expire in 15 minutes, I take it you have already made up your mind...
I recently (yesterday) underwent a similar situation. I cracked a frame and received a warranty replacement frame. Since my old bike was more than a year old, the shop wouldn't cover the labor fees for switching everything over to the new frame. Rather than pay the shop $70 to do the swap, I decided to buy the tools and do it myself. Although I happen to be quite mechanically inclined, this was the first time I have ever done a complete bike tear-down/rebuild. I found the experience to be very enjoyable and definitely easy enough.
So yes, I found parts swapping to be rather simple. Critical areas include not messing up the headset bearings, and getting the deraileurs dialed in properly. Just take your time and be careful, and you'll be fine. And don't forget to consult the internet for step-by-step instructions.
Now I'm just waiting on a seatpost, collar, and some cable-housing... Easy as buddah.