There isn't as much of a difference as there used to be. With the Novas using SLR reflectors, the difference in overall output got a lot smaller. The only major differences how is that the Sundial has built in timers (not always a plus, especially when they fail), fan cooled, and moonlights, while the Nova doesn't.
I have a nova extreme which is fan cooled with no moonlights. I was looking a Sundial for my 22 but since im upgrading to a 150 I'm just going to shut that tank down.
Personally, I would go with the Sundial. More for your money. Replace the bulbs though because the stock Current bulbs are horrible.
If that is the case (lights suck) buy from somewhere you can pick the bulbs that come with it. Silly to order a light then turn around and put another $80 in bulbs.
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