Good prices. I built the Tractor and Trailer last year (got at Amazon prices). It was an enjoyable build, and it has some good parts (differential etc.)
I look at Technic sets in two ways...
1. Fun to build, to learn some new techniques for construction.
When I look at the prices of sets I try to find sets with the best cost per part ratio. The set John got for ~$60 US was about $0.05 US per part. The usual price is about $0.10 US per part. so for me when I look at prices, the closer I get to $0.05 US per part the better. But that is not always my gage as to whether I get the kit. Sometimes I get it just because I want to build it (then have parts for later).
I usually only keep sets put together that I intend to NXTify at some point. I like to have 2 sets of models I want to NXTify so I can leave one together as a reference and build and NXTify the other, but this is not always practical or economically prudent.
Good find on the Technic sets prices though. Too bad I'm all bought out at the moment.