This was my experience over 3 years ago.
My friend, who is now my coach at this time, provided me about 4 places to check out in Madison. The first store I went to was Trek East. I thought of several things when I went there - I would support the local economy, Lance was all the craze for being their spokesperson and rider, and the bikes are pretty good.
I walked in, met up with a young (mid-20s, tops) sales rep, and talked about getting my first tri bike and was asking about carbon-style vs aluminum. I could sense the first thing that went through that guy's head was "TT" or "Tri bike" and "carbon" and, immediately, without asking any real questions, directed me to the last couple of TT bikes that they had at the time (the one carbon TT that was manufactured in Taiwan at the time that was less costly - the ones that had some minor issues because of the type of carbon base they were using, which I didn't know about at the time until I did some research on the Internet a day or so afterwards, but I digress). The frame was about a 55 cm, which would have been small for me - I'm 6'3".
The salesguy wanted to sell me a bike and then ask questions later. I continued asking some other questions about fitting and other stuff, and he showed that they did the fitting in-house there, showed me their setup area and talked about the cost, etc.
I went to a couple other places and finally made it to Cronometro. Being a newbie, I WANTED A TRI-BIKE! The person I spoke with was Craig. Best person I ever spoke with, and sure was lucky he was there at the time, had a free moment, and spent the time talking with me. He provided a LOT of feedback and asked me questions of what I was considering before luring me to any bike. He even stated that he would NOT even sell me a Cervelo (which is one of a couple of different brands they offer), if the FIT didn't work!
He sold me right there on getting the FIT first, then matching me up with a bike! If the Cervelo didn't fit, then they would fit me on whatever bike I would get, even a Trek if it would work. Turned out that the Cervelo was a fit that would work. The cost was around 250 bucks, and a portion or all is applied to a bike that you would purchase from Cronometro. You schedule a time with Craig, and can spend close to 2 hours getting fitted.
What's the point of all this jabber? I'm not familiar with the persons at Trek, and am sure that they would fit you fine in their Trek setups. But, if there was any person that was worth working with for a fitting, Craig from Cronometro is the man and well worth money and time. Just my honest opinion.
Good luck.