Stock poly: they stretch a lot and are a pain in the butt to initially break in. Smoothest to the touch and my preference.
Thunderguts: white, not stretchy, reach stability very quickly. Super sticky
Silver rumblers: grey, not stretchy, quick stability, sticky but not as bad as the thunder guts.
As for tonal differences, there's certainly differences, but I'm not great at describing tone. There's 5 mega threads on the ubass. Anyone at all interested in getting one should read through them. There's a whole lot to know.
And there's silver plated copper wound strings with a silk core from pyramid.