I know, haha di ko naman din nirecommend si GT2. pero, kung versatility kumbaga, I think I'd go with the GT2.
Hahaha. I have had the chance of owning the GT-2 several times and have tried it on several amps as well. Totoo nga, mejp kakaiba siya pag sa front ng tube amp mo ilalagay. Although maayos kung nasa fx loop. Pero paminsan makakakuha ka din naman ng maayos na timpla kahit sa front, helpful kung may external EQ pedal for better tone shaping.
As far as the Shredhead is concerned, or any other MI Audio Crunchbox clone, may mga amp din siya na mas binabagayan.
Handy lang yung GT-2 for those who would like to use it more than just by plugging it sa amp.. Pwede siyang DI box at amp simulator sa mga mixer, afaik, at pwede ring direct na nakaplug sa mga audio interface for recording.
Pedals are fun, thouh.. trial and error, test and see where it works best..