I think I'm pretty happy with my drives/delays/verbs and have some room on my board for a modulation effect. i'm mainly interested in either a tremolo, phaser or vibe pedal, but don't have too much experience with these effects. which one would you choose and why? can one be made to sound like the others? any particular models you would recommend? if it helps, my band plays ambient, spacey rock/alternative music. any and all suggestions welcome!