Not yet, though I work a lot with a Zoom H4 and love it...
Main differences...? H4 will play back four tracks and do bouncedowns (but only record two at a time), H2 is two track only. H2, more mics and recording modes, H4 more internal effects.
Both are killer, but if you have a hankering to overdub a part AFTER you make your initial recording (if you aren't already using a DAW or built-in audio multitrack recorder), the H4 seems the better bet...
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An arranger is just a tool. What matters is what you build with it..!