I've got an aquaone cf-1200 external and an aquaone at-882 internal. both are rated at 1200 lph. Both are practically silent running and the external has to be felt to check it's actually working.
The flowrate on my cf-1200 isn't particularly good at the moment. I'm off today so going to take it all apart again and re-check the hoses, clean the impeller etc. I'll let you know, but as it stands i couldn't recommend it to anyone, though i'm pretty sure at 450 lph i've got a problem somewhere.
Excellent flow on the at-882 though, and the only time i've heard it was when I put too much fine media in it and it started spluttering.
Sorry, can't help on the price either but i've seen them both (used) on ebay for about £50 total