I recently bought a return pump for my new 180g. I looked over threads and reviews, especially on the salt side, and made the decision to stick with AC pump. I had good luck with my sicce 3.0 and got a 5.0. Even with more and more good reviews on DC return pumps there are still a lot of bad experiences and failures and a return pump is too critical to have fail for me. Especially as a good AC pump lifetime is generally measured in decades.
I'm sure DC will have its place soon - it's great for powerheads, but I have never wanted to vary my return pump flow, they don't have as good height performance, power savings isn't huge and I personally don't want another controller that I will never use under the stand.
I like new tech, but not on something that my filtration, aeration and heater are linked to in my sump. With a powerhead I figure if it breaks the Chinese ones are cheap enough to replace and give it a try - and I have good results with them, but I don't want to risk it with a return. That pump goes and the tank goes.