I have had a g-tech since July last year. Love it and was doing a 12 mile round trip on it every day but now have moved closer to work and can walk in, still use the bike every now and again though.
For me it put the fun back into cycling, was getting too tired on my normal bike and was hating the journey. Got the g-tech and actually look forward to the journey.
Edit: Forgot to say the things I have changed. Replaced tyres with Marathons but on the originals I didn't get a picture for about 6 months. Pedals as they started making a noise and that annoys me. Grips on handlebars, far to hard for me. Seat, put my brooks on. Put a stem extender on to make the handlebars higher.
Dave