Considered top of the line by many are the Vortech PHs. An MP10 would get decent flow, but an MP40 would allow more adjustment in a tank that size. These can not be aimed since they mount flat on the glass, but Vortech claims that is not an issue since they have such a wide flow pattern.
Then there are the Tunze PHs. They take up more in-tank space since they do not have a dry and wet side, but they are great. They can be aimed as needed, and I always keep one aimed towards the surface to give the aggitation needed for oxygen exchange.
Koralia powerheads are at a much lower price point, and many have good luck with them. Jebao is also a Chinese brand that is a direct rip-off of the Tunzes, and lots of people have been doing group buys and talking about how good they are for the price.
At the bottom of the list is the Maxi-jet models. Inexpensive and barebones.
Remember these things have to run for years inside a salt water environment. They will probably only come out of the tank every 6 months to a year for cleaning. Multiple PHs are better than a single one with the same flow rate since you can better set up the flow you need.
My setup on a 150gallon is a great return pump, 1 Vortech MP40, 2 Tunze 6125s. I picked up everything used which help offset a lot of that initial cost.