I have KAB's older rubber record grip (since replaced by this one), and for the $29.95 I paid, it lowers surface noise, reduces record slippage (better pace, tempo, and transients), and makes really thin pressings such as RCA Dynaflex records sound just like full weight LPs.
IMO record weights and clamps would have different but overlapping effects. A record grip like I have absorbs vibrations coming up the spindle, clamps the record to the mat, and absorbs resonances from the record itself. It also has the advantage that you don't have to adjust the loading of a suspended turntable.
A record weight would do similar things, but the mass of it changes the resonant frequencies of the mechanical aspects of the playback. This could be for better or worse, or for both.
Then there are the ones simply designed for resonance control, that neither clamp nor add a lot of weight, such as the Herbie's Supersonic Record Stabilizer.
IMO record weights and clamps would have different but overlapping effects. A record grip like I have absorbs vibrations coming up the spindle, clamps the record to the mat, and absorbs resonances from the record itself. It also has the advantage that you don't have to adjust the loading of a suspended turntable.
A record weight would do similar things, but the mass of it changes the resonant frequencies of the mechanical aspects of the playback. This could be for better or worse, or for both.
Then there are the ones simply designed for resonance control, that neither clamp nor add a lot of weight, such as the Herbie's Supersonic Record Stabilizer.