Vandersteens are considered very very good speakers, that provide excellent value. They tend to be very plain looking though. They always get very good reviews in the trade press.
I have hear the 3s, 2a, and 5's many times at various trade shows (CEDIA, CES, RMAF, etc.) and they sound, well, very good.
Vandersteen emphasizes time and phase alignment. The former generally means that the acoustic centers of the drivers are all the same distance from your ear (so that the sound arrives at the same time). The latter means that all of the signals are in phase. This is argued to provide a very smooth integration of the frequency responses of the drivers over the entire audio spectrum, so that they in some sense "behave" as a single unit.
The other nice thing about the V's is that many of them can be 'upgraded' by the factory for improved performance.
The company's been around for many years as well, and is still run by Richard Vandersteen himself. All good signs.
Vandersteen also has an interesting patent on his drivers, in which the magnet and spider structure are designed to be very narrow, so as to not block and reflect the back wave of the driver back toward driver's surface. This is said to reduce distortion.
Check audiogon for used V's.