Both the treks are tiagra level shifters - the dolce that is used has much better components for cheaper.

There are lots of people that buy tiagra and like it, and there are lots of people that buy tiagra and absolutely hate it because it can be persnickety shifting and it can take more adjustment. I don't know what type of person you are - if you're the type of person who gets a bike and is likely to want to start upgrading components, I'd say to get a bike with 105 level components minimum. Most people are fine with 105 or so level shifters because once you get shimano components at that level, the next higher up level of shifters (ultegra) don't necessarily actually shift any better, they're just lighter in weight.

That being said, $900 for a used 105 level road bike is possibly on the high end. If it helps, one of those sold on ebay recently for $800:
http://cgi.ebay.com/Specialized-Dolc...item1c10b14b20

Someone selling on ebay probably paid 10-15% of that in ebay fees.

So if you could get her down to $700-800 range for that specialized dolce that would be a much better deal.


Which bike felt better when you rode it? The specialized bikes have the zertz inserts which should dampen vibrations and possibly keep you more comfortable on longer rides - aluminum bikes, even with carbon fiber forks can be very harsh feeling especially if you have chip sealed roads around the area.