I got the GGtb last week,It's great!(nothing so far beats the provari tho Imo)the opposing magnet button (14$ bought when I ordered the GGtb)is a work of genius,nothing to break,magnets never(?)get weak. with a 1.5-1.8ohm 510 it's pretty close to the provari @ 5v with a std 510.
the best part,it's not real expensive(comparativly)