Originally Posted by
Radharc
I am a long-time owner (8+ years) of an early year second generation Aqua Terra -- it has an 8500 movement but no Si wheel. So, I don't have experience with the watch you want but I have lived with the 8500 for a while. I also wear it -- for the most part -- in an office environment, usually business casual but often with a suit as well. The alleged "thickness" of the watch has never been a problem for me, and I do also wear other watches that are thinner so it's not just a matter of me being used to it.
In my experience, the 8500 is rock solid and keeps amazing time (mine has been +/- 1 second per day). It's also a very pretty movement, at least as far as mass-produced movements go. That said, all the reports of the 2500D I have seen are also very positive so, day to day, I really don't think one is better than the other in terms of real world use. The 8500 does have a longer power reserve, but that won't matter very much if this is your primary watch.
One thing I haven't seen mentioned in this thread -- the 8500 has a "jumping" hour hand. This means you can move the hour hand forwards and backwards in one-hour increments without stopping the movement. It is fantastic for travel. But, it means that the watch does not have a quick set date. You set the date by moving the hour hand forward (or backwards) 24 times. I really love this feature of the movement, perhaps because I travel a fair amount, but I have seen other folks complain about the lack of a quick set date. Just something to consider.
In my experience, this means you should get the 8500. Otherwise, you will get the 2500 and still lust after the 8500.
This is not accurate. The 2500D is still a three-level co-axial movement, and can only be serviced by people qualified on co-axial movements.