I was looking for a high flow powerhead without the high price of the Tunze, so naturally I sought out the Rio Seio line of products which have had some fairly stellar reviews thus far.
Having never owned a Seio before, I was quite surprised of the size and weight of the unit. The unit measures ~8x4x4 which, to me, is quite a step up size wise from the Maxi-Jet 400s that I usually deal with
The unit weighs approximately 5lbs or so--you'd better make sure its well secured to whatever you are mounting it on! Personally, I'd forget about the included suction cup hangers and use the ones that clip onto your tank walls/trim.
The flow from the unit is quite amazing, but not as dispersed as I thought it would be. I've read cases where others have put corals fairly close to the output of their Seios without any ill effects. I can't say that I've had the same success. Even at 5" away, the flow is still quite strong...it can flip over frag plugs, snails, fish, etc with ease
Power consumption is in around the 80W range or so. Not too bad considering my Mak 4 pumps uses about 100W or so but has half the output.
So, in summary:
Pros:
Mega flow (2600GPH!)
Cheap cheap
Fairly low power consumption
Cons:
Mammoth size
Laser like water flow
Extremely short power cord!
