Not a huge effects user, but I'm thinking of picking up a tremolo pedal. The particular effect I'm thinking of is what you get on "Next Girl" by the Black Keys. Budget is limited, so can anyone recommend what's best of the under-$200 (and preferably under-$150) pedals? I'm looking at the Hardwire TR-7 and the Boss TR-2 so far, but open to suggestions. Thanks!