Using the search function here, you will find countless threads talking about those pedals.
But basically:
1. I admit BIG BALLS is a cooler sounding name for a bass pedal
. Well, it's a double envelope filter, or envelope follower, I never know... So it reacts to your playing intensity, and offers an integrated distorsion do harsh things up. Very unique because it generates a specific tone, that some may not find limited, not very versatile or easy to use in a band context. In brief, you might get bored with it. Like others said, searching and hearing samples here is the best way to know if you really want this pedal.
2. Classic phaser pedal, you can't go wrong with it... You know what's a phaser, right? A mod or two can improve the general tone, but bersonally, I am very satisfied with the pedal as it is, and I don't care about the bypass, which is pretty bad, according to BPFs here - By Pass Freaks
3. Sounds also like a good phaser choice, but I don't really know the tone of Small Stones. About the size of the Phase 90, it has one more feature than the MXR : the "color" switch.
