Okay, as far as I know they felt fine to play on, and I never heard of them tearing up your joysticks. They have become slightly overcome by events, IMHO, though.
The biggest drawbacks were that they at least didn't enhance the looks of your panel, and if you were playing an 8-way game, you had to store them somewhere and then figure out where you put them when you wanted to play a 4-way game. And then there was the time involved in bolting them down and unbolting them (thumbscrews, but still).
IMHO, all of the following are better options (basically in order):
Dedicated 4-way and 8-way sticks - Most (all except Karate Champ?) 4-way games used a single centered stick, so this isn't a bad option and requires no reconfiguration.
Ultimarc E-Stick, J-Stick, T-Stick (Mag-Stick) GGG Omni-Stick - Good options if you like the feel and have access to the underside of your CP.
Ultimarc T-Stick Plus, GGG Prodigy - Good above panel restricted stick, if you can deal with the relatively short travel.
Ultimarc U360 - Should work well, but reviews are pretty mixed and too early to draw definite conclusions.
GGG GP-Wiz49 and 49-Way stick - Automatically (with Set49Way software) switches to correct mode for game with no user interaction required.
The only thing you are gaining with the OSCARS is the true physical restriction, but from what I have read, the GGG 49-way stick and interface works well without this.