Just wondering if anyone had any strong opinions as to whether either spinner was superior... the Ultimarc Spintrak or the TurboTwist 2 from Groovy Game Gear.  I've purchased from both stores before and had nothing but good experiences so that's a non-issue.  The base products seem very similar and are nearly identically priced but Ultimarc's knobs and flywheels are a few dollars higher, and their selection of knobs seems smaller at the moment...  Apparently the Spintrak is USB 2.0 and the TurboTwist 2 isn't...  is that significant enough of a difference, in actual practice?
Thanks for your thoughts!