If 320gph means 1200lph -> then you're talking about the Seltz L30 II which i've been using for more than 1y and half.
Its flow characteristics are exactly the same as the Eheim 1250.
It's running a bit hotter.
It's making a slight noise, nothing disturbing, but i can hear it. Noisier than Eheims, indeed.
It produces a lot of vibrations, i had to suspend it with rubber bands. I think Eheims and other centrifugal pumps have the same problem though.
The impeller *has* to be glued. I ran through 2 shaft+propeller sets though, as they tend to wear and produce a deep "scratching" noise over time.
The casing is nice and small, connections (inlet / outlet) are standard and compatible with Eheim products. 1/2" inlet and outlet, and a nice tubing attachment system, but not compatible with thick-walled tubing
Price wise, i had it for 1/3 of the price of a 1250, that was the deciding factor for me. Today i have less financial problems, i'd maybe opt for a 1250, who knows.