Re: Rebuilding the Tommasini Fire

Tom Kunich wrote:

After I accepted that Campy had no intentions of supplying 12 speed
parts. I decided to switch bnack to 10 Speed 6800 Dura Ace. It was
very difficult to get long arm rear derailleurs but I solved that by
getting 105 10 speed rear derailleurs. A fraction of the price and
with actually better shifting.

I just got my own bike out of the shop after a long-overdue tuneup.  I got this one in 2005 or 2006 with 10-speed Ultegra on it.  I have several thousand miles on it, but until now, I had the original cassette, and I think the original chain, as well.
When I talked to the shop, we found (not surprisingly) that there isn't any 10-speed Ultegra around anymore, so we put in a 105 cassette, and I'm sure that will be fine for what I need.  Many years ago, I had a bike that had been built with Shimano 600 on it, and when the front derailleur needed to be replaced, we did a 105 on that, as well.
Historically, I know that the difference between Dura Ace and Ultegra is that Dura Ace is the lightest, and where Ultegra is slightly heavier (but not really enough for me to notice), and more durable.  I've never lived with a full 105 set, but I can guess that the same principle of weight/durability applies.
However, after this experience, I can also add the impression that Shimano may keep 105 around longer, and that for replacement parts that are compatible (especially for older stuff like mine), most of what's out there is likely to be 105, and as you suggest, may actually perform a little better and last longer.  At least for drive train parts.  I have no idea if that might or might not apply to shifters or brake sets.
Smith