the only thing i personally dislike about the system is the daily maitenence.
You have to dose multiple solutions daily, as well as pump the reactor once or twice a day. Doesn't take long, and i didn't think it'd be a problem, but where you run into a bit of a problem with it is the initial phase.. you're supposed to dose in front of the reactor, and only when it's on (it switches on and off in 3 hour intervals). So you have to be home, and ready to dose when the reactor is on... you also need to pump it once or twice a day when the reactor is on.
Doesn't sound like a big deal, but for someone with a bit of a busy lifestyle, it can be a bit frustrating at times.
The other thing is make sure you place the zeo-reactor down wind of you're skimmer..