Positives:
Reliability:
I’ve been beating on the same Velodyne for 4-5 h/wk for 9-12 mo/y for the last 20 y. I’ve had to send the head unit back to Bruce for repair twice, both times partially due to my own stupidity (never a good idea to connect a circuit board to a live power supply). On one occasion I also had to repair the circuit board in the base myself, after my wife burned out a resistor the size of your fist by doing “strength endurance” intervals as prescribed by her coach (high power + low flywheel speed = high current draw). Other than that, I have not had any problems.
Accuracy:
I’ve cross-checked the Velodyne against various on-bike powermeters on numerous occasions (almost every time I use it, actually), and have found to be very accurate (usually w/in ~1%) as long as you 1) warm it up thoroughly then 2) perform the coast-down calibration.
“Road feel”:
The rapidly-spinning 10 kg flywheel provides roughly one-third of the inertial load experienced outdoors, which makes it one of the smoothest (if not the smoothest) trainer ever made.
Negatives:
As other have indicated, the (original) screen display is rather antiquated and can be hard to read, and swapping different bikes on/off the Velodyne is more work than with many other trainers. It is also larger and heavier than most other options, and thus is best if you have sufficient dedicated space for it (ideally on a concrete floor). Unlike, e.g., a mag or fluid trainer + on-bike powermeter option, you need access to 110 V power - OTOH, unlike, e.g., a CompuTrainer, the only external wire is the power cord (so no tripping over/snagging various delicate wires when getting on/off the bike at 6 a.m.).
Bottom line:
The Velodyne has been the best cycling investment I have ever made, and should mine die tomorrow I’d immediately be looking to somehow acquire another one.*
*Actually, I’d just use my wife’s, since we have two and she hates riding indoors. 