Greetings everyone.

I had been biking in college (15 years back) and have gotten back to it about 5 months back. Since work and my laziness does not allow me to bike over the weekdays, I bike over the weekends on a Trek 7.3 (Shimano Deore derailleurs - 24 speed) which I bought in the summer of 2009. I cover 80-100 miles regularly, mostly over bicycle trails and some county roads at an average speed of 14.5 mph.

Recently, I started riding along with a local bicycle club. In the rides I have been around, I have always been lagging in the uphill sections. I am mostly OK in the flatter sections and am able to keep up with the group. I wanted to upgrade to a better bicycle and went to a LBS to get a fitting done, so that I can look for the right size.

After the fitting, the owner showed me a Felt Z35 (2009 model), with a price of $2100. From what I researched, this seems to be a very reasonable entry level bike, but with some shortcomings when it comes to accelerating. I am not into the latest and greatest, so I am OK with the last year's model or the year before that, as long as the bike satisfies my needs, which are:

1) Comfortable for a 50 mile ride at a stretch
2) Ability to keep up with the pack on uphill sections
3) Should not outgrow the capabilities bike in 12 months and need an upgrade

My questions are:

1) Will the Felt Z35 with the Shimano 105 derailleurs help on the uphill sections compared to my current settings?
2) Are there any current owners of the Felt Z35? If so, can you let me know of your general riding terrain (roads, trails, uphill/flat etc) and how you feel about the bike?
3) Are there any better alternatives?