I have a G4. I bought it off ebay as well--it came from Florida. It was $340 (including shipping) and I sent in the $50 MIR. Saved over $175 from leslies, not counting the MIR.
It seems to do a decent job with my pool. I installed salt and then got this and then fired my pool guy. I add acid every other week or so--haven't had to vacuum it.
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