I'm starting my twelfth season with my original Computrainer and I am very happy with it. I've had absolutely no issues with it at all; I'll ride indoors on it exclusively from November to March, and even in season I'll ride it two to three times per week, mostly for interval sessions. The hardware is solid; many might complain that the native CT software is a bit dated, and some complain about its serial interface. In practice, though, the system is bomb-proof, peripheral hardware requirements are low, and there are some interesting third party products that enhance the virtual reality component of the system, if this is something that interests you. I find the greatest value (and which comprises my greatest use) of the CT is the ability to program ergometer sessions. CT's ergometer mode forces one to ride at a prescribed wattage, regardless of cadence and gearing. So, I can structure a session that might include a 20min TT effort at 390 watts in which I have to ride at 390 watts, no matter what. Another feature that I frequently use is the ability to compete against a virtual rider--some times, I'll race myself against a saved performance, or I'll draft a pacer to simulate motor pacing (which I find replicates the experience very nicely). Finally, I'll frequently program in upcoming courses to familiarize myself on the terrain and to work on pacing strategies to specific races.
After approximately 10 minutes, one does a calibration of the unit's press-on force on the rear wheel. This is a simple process that involves an acceleration to 25+ mph, and then a coast to the rear wheel stops. Results from my CT sessions appear both accurate and consistent.
Now, some will encourage you to purchase a trainer and power meter, and say that you'll have all that you need. For me, the value of the CT's ergometer mode more than justifies the cost of the system. It is an important part of my training.