Well, I finally splurged and bought an EcoTech Marine Vor Tech pump. It is really cool!! It is a pump motor magnetically coupled to a propeller housing. Motor outside glass, prop inside. No heating of water and unbelievable flow. I had two Powersweep 228's in this 20 gal tank. The idea of the Powersweep's is a fundamentally sound one, but in my experience, needs more development. They tend to quit sweeping often, and need to be turned off and on again a few times to start sweeping again. But beyond that, they were huge powerheads for the amount of flow they produce. Lots of heat and wasted space. If you used their prefilter foam assembly, (and it tended to work better with it) they were even more of a pain because they needed cleaning nearly every week and they themselves were quite large. They supposedly are good for 270gph, but they sure seemed weaker than that. The alternating flow when working well was nice though.
I wanted to eliminate a chore and they were one of the most time and labor intensive chore I have. I have a basically low maintanence tank with all of my filtration coming from a very efficient 10 gal refugium and a DSB in the main tank. It has been a very stable tank with a 30-40 lbs of very nice Marshall Isle rock. Water parameters are always zero on nitrates/nitrites/phosphates/ammonia etc... with only adding Reef Builder for carbonate alkalinity, Sealab #28 replenisher and occasionally #14 for a ph increase. My tank seems to want to run between 8.0-8.2. Top off every day with ro/di water and that is it.
This tank has a Bangaii Cardinal (Pterapogan kauderni), Yellow Wrasse (Halichoeres chrysus), Royal Gramma (Gramma loreto), and a Hectors Gobie (Amblygobius hectori...thanks Aquarium Oddballs!). Also have lots of cleaning guys in the form of various snails, brittle star, crabs, shrimp, pods etc. Corals include many various soft and hard corals, both LPS and SPS. I'll give a list later, but suffice it to say that this is a very full tank and I need to expand.
Which brings me back to the Vor Tech. I really wanted to upgrade to MH from my current 130wt PC light |( SPS and baby Maxima 1/2-1" under surface, clam has over doubled in size, but that is another post). But I figured that when I get larger tank, I would probably want a 48" assembly, too large for my twenty. So I opted to spend a kings ransom on a piece of equipment useful in any size tank I might get. This pump's flow is incredible. It will literally push water over the sides if the flow is turned up high. The inflow/outflow is broad, smooth and since I have to have it aimed at rocks, I seem to be getting little currents everywhere. I know it is only one day's use, but so far it seems to be the bomb! Quiet too, and oh yeah, made in USA!
Well this is getting a little long winded now, but thought ya'll might be interested in this new purchase. Later....Tracy

Sounds like an awesome pump.Its always nice to have good equipment so when you do upgrade at a later date it doesnt hurt the wallet as much.