I love mine, seemed a bit of an indulgence at first, but justified it by cancelling gym membership. I use it for fitness rather than competition training - I'm not a racer, but I have been getting more "scientific" with it of late.
It is a great piece of kit, allowing you to focus on the type of training you want, whether it be based on watts, cadence, HR, or slope. You can ride to the stats in "Catalyst" mode, but I prefer to put the VR mode on and ride the various terrains, racing against your own previous efforts is a real motivator, and it is true, the time really does seem to pass a lot quicker when you're "in the game"!
It works really well for me as I'm a bit time-poor, what with work and family commitments, I can pop into the garage and fit in an hour or so of good quality exercise without getting into the badbooks, win-win.