I ran a Rio2100 for 5 years now in my 40 gallon sump of my 240 Arowana tank and it's worked fine. It's pumping the water 4 feet back to my tank. It only draws 37 watts and pumps 692 gallons per hour at 0 ft head, but 375 gallon at 4 ft (said so on the box). It's pretty efficient as pumps go.
My only complaint is that these pumps don't restart 100% of the time after switching off and back on. This becomes more often after a couple of years of use. You have to take it apart and reassemble it to restart it. So, this makes the Rio a pain for applications where you have to restart it often. Having said that, I still like the Rio brand for the price and reliability if you keep in on all the time.
I have 2 Rio 2100 and a 1100 currently running.