I added the Technoweight to my RB250 and it made a BIG difference. Bass tighter, tighter, less bloated, yes, but the subtleties it brought out are amazing. The tone on trumpet or sax had more texture. Drum taps have more in depth ressonance. Nylon guitar strings have more 'personality'. Hidden things come to fore like the softer touch of Bill Evans opening piano ... nuances are where the charms is.
I think I hear the same comments made pro as to any of these counterweights with the center of gravity at the cartridge level. It is said that the lower center of gravity makes it track better thusly the sound reproduced is more detailed.
I have not tried any other but looked and many many reviews before deciding on the Technoweight. The lastest of the weights are the Groovetracer
and the Kerry
on sale on the classifieds.
The word is that these are 'better' that the Technoweight but that the Technoweightn betters the Origin Live weight. Who knows without trying one? It was easier for me to decide on the best that was being talked about at that time.
And besides the Technoweight is not as ugly as those other two: http://home.comcast.net/~omaille/lester/tw.jpg