I just set up three MP60W's on my 150 gallon tank, and considering everything that has already been mentioned in this thread (with emphasis on AMAZING customer service) they have been well worth the investment.
PROS:
1) very wide spread flow. They move enormous amounts of water at a relatively low velocity.
2) Watching the Ecosmart modes in action is wonderful. The standing waves that these pumps can create I have not seem matched by ANY other pump OR wave box.
3) They just look cool
4) Customer service is the best in the industry ( I know, because I have taken advantage of it)
5)"Upgradeability" - Ecotech has done an outstanding job of building their pumps such that you can upgrade and repair them as necessary. They are making new controllers that you can put on their old pumps to make them better. What other companies do this? There are very few.
6) Resale value; take a look on the used drygoods forum. You typically can get about 2/3rds what you originally paid for this pump. Even more if you bought it used. This is unheard of.
7) No heat transfer to the tank. Most would consider this a moot point, as most powerheads have a negligible watt-draw and thus a negligible heat transfer. Never-the-less, comparing watts to heat added to tank, the Vortechs are very low.
Cons
1) Price, although this is subjective. They are expensive, but your paying for the package deal. Think about it. Your buying pumps that talk to eachother. Wirelessly. Your paying for the customer service, the warranty, the research it takes to build and improve them, and the forethought to keep them upgradable in the future.
2) It is too bad that they can't be pointed in different directions. This is not an oversight however. Just something that is inherent in the design. Most of this is compensated in their incredibly wide flow.
3) There are no cords in the tank, but if you run the pumps in their recommended ecosmart configuration, there will be pump cords attached to the side of your tank. It is a touch unsightly, but an easy tradeoff for me. It is a big deal to some.
Some Things to Note:
a) There are many who will tell you that their Koralia's are just as good as any other power head. This is simply not true. Right before I purchased my vortechs, I had bought 2 Koralia II's (new style AC). Out of the box, one was extremely loud (louder than all 3 or my MP60's at 100%), and the other would spin the wrong direction half of the time it started. Koralias are ok pumps, and with enough, and assuming that your luck to get one that actually works, you can set up sufficient flow for any reef system. You have to compare apples to apples here, and comparing a Koralia (even the controllable one's) to a Vortech is just silly.
b) If you buy 2 MP40's now, you can upgrade your tank to about 150gallons and not have to buy another powerhead. This will save you money in the future. If you don't have the $$ for 2, just buy one, and replace one of your Koralias with it. Buy the second when ever you can.
c) If you know anyone with a vortech, stop by their place. Listen to them and see if the noise will bother you (probably won't). Watch them in different modes, and listen to what the owners have to say about them.
d) Do some research on the Tunze pumps too. I have never used them, but I am sure they are outstanding pumps as well.
e) Keep in mind that although 2 MP10's will be sufficient for your tank now, if you go any larger than a 55 you will either need another MP10 or you will have to go up in size on one of your Vortech's. Again, I would suggest buying a single 40 now, and buy a second one when you can afford it. Also keep in mind the tank wall thickness during your research. Different sizes have different maximum tank thicknesses on which they can operate.
Hope this helps, and good luck with your decision.
Nate