So, I've got about 100 miles on my GT already. I've swapped out the crap tires and have both a set of 35c road tires that I used on my 29er for a charity ride once and are way better than stock, and a over the past weekend put on a set of Schwalbe cyclocross tires that are one of the less aggressive tread patterns I could find. I've put together a 13-15 mile ride, depending on exact route, that I've been doing semi regularly. Its got a few miles of gravel and some mild singletrack. I've had some funny looks from guys on mountain bikes when I'm on trails. I also swapped the stock 11-28 cassette for an 11-30 for a slightly easier spin up steeper grades. And added some bottle cages that match the green highlights.
Overall, still happy with this bike.
Now that the weather is mostly nice, I've been using this for grocery runs. Way more enjoyable than driving.