I've had the AC2 from Neptune for three years now. I'm going to upgrade to the AC3 (non-PRO).
I use the DC4's but the newer DC8 looks like more ports for your $. One thing I should mention is that the original DC4s would blow fuses on IceCap MH ballasts. This drove me nuts but they fixed it on the DC4HD with higher current capability.
Also, their DC units can't switch a decent sized chiller for very many cycles without blowing the fuse. I bought a 110v relay with a 1hp contact rating and that has never failed. You could also use an X10 module with the appropriate rating but the DC switched outlet blocks are very reliable, signal wise, compared to the X10 modules. Some people don't have any issues with the X10 but others do and it can drive you mad.
I thought I would use the Neptune to just flip the lights. Then I decided that I didn't like working on my tank. So ... the Neptune now switches 2 MH lights, 4 sets of PC lights, 2 wavemaker pumps (MaxiJet), a 1/4 hp chiller, the CO2 valve on the calcium reactor, the pump on the calcium reactor, the pump on the skimmer, the UV sterilizer, the main pump (turned down during FEEDing only), the 120v solenoid on the valve to the RO/DI for makeup water, and the peristaltic pumps that dose iodine and phosphate binder. It does all of this based on time, temp, pH, and ORP.
I do exactly NOTHING on my tank. As I also have a Nitrate Reactor, I don't even change the water ... ever. And since my wife drops the food cubes in ... I am officially a slacker. All thanks to the Neptune.
Sure, I have to replace the Iodine and Phos Binder bottles every once in a while, flush the RO membrane occasionally, and clean the skimmer now and then ... but that's not too bad.
My Neptune AC2 also eats 9v backup batteries too often and it's clock gets off time too quickly. But I hear the new AC3 fixes all of those issues. Hence, I'm upgrading. I would highly recommend the Neptune stuff.