I am also looking for a pump and Rio really caught my attention due to it's low price, low power consumption and high output. But after doing some googling around I discovered a lot of problems like overheating, melting, impeller stuck. But those were like 2002, 2003 threads. Can some recent users feedback on Rio pumps especially those using it for more than a year?
For the other pumps you mentioned I think the price is almost the same for the same performance so I suggest stick with Eheim. I am Eheim user on 2ft for 1 year now without problems. But I am still searching for a new pump for my planned 4ft.