Before you commit, three questions:
1. Have you viewed and/or rode the GTR5 in the flesh? For instance I really liked the aesthetics of the 2010 GTR3 - which was bright red and silver in pictures - but when I actually test-rode it it turned out to be maroon and a kind of drab grey. Plus it didn't ride well for me. So in more than one way you need to see the bike first hand.
2. The chainset is 52/39 which means the lowest gear you can achieve is going to be pretty high, so that would be fine if your cycling is flattish and/or you're really fit, but if you've got hills or prefer a more sedate pace, it may be too high. A good shop may be able to put a compact double on instead which would give you lower gears for climbs but still high enough for most of the speedy stuff.
3. The GTR I think is a bit heavier than comparably priced bikes from other big brands like Specialized, Trek, Cube etc. Worth knowing if weight is important to you.
Cheers
Stu