I have two of them, and I like them a lot. They were a little overpriced, even at the discount I got them at (only paid $20 each), but I like them well enough. If I could go back and do it again, I'd buy small AC filters instead, though. You're right about the flow control REALLY making a difference. I drilled mine out, and the difference was wild. Also, I changed the hoses out for longer ones, but I found that they don't fit onto the intake & spraybar. The hoses that come with it are smaller at the end that attaches to the filter and bigger at the end that attaches to the intake & spraybar. Had to buy adapters and everything for them to fit.
Both of mine leaked, BTW, and I had to seal where the hoses connect to the canister with plumber's tape (teflon tape). One of them didn't leak for 3-4 days, THEN I wound up with water all over the floor.
But, they're dead silent and I don't have to listen to water splashing like I would from an AC.
Long story short, at $20 each and $8 worth of hoses & adapters, water damage to a wooden dresser since it leaked, and $1 for teflon tape. . . I'd have probably been better off buying an AquaClear. But, for dead silent running on my clawed frog tanks, and no clogging like lots of HOBs do, it's worth it.
