If you're looking at a two bulb fixture, check out these:
http://www.hagen.com/pdf/aquatic/GLO...Program-EN.pdf
I do think the Coralife unit is built a bit better (i have one) but it doesn't have particularly good bulbs. The Hagen one doesn't come with bulbs (I picked up 39 watt dual bulb today for $129.99 @ Pisces). So, if you want to purchase quality bulbs the Hagen might be the way to go. If you're content to use the Coralife bulbs, I do think it is the better fixture of the two. I've personally replaced all of my Coralife bulbs with APi bulbs.
It won't impact your electricity bill too badly: 5-10 bucks a month or so (but I advise you do the math and determine this for yourself . . . I did the calculation in March, and the rates may be quite different now). You can offset the power consumption by turning off your computer when you're not using it (that alone could save you almost $15 a month), and unplugging your cellphone and other chargers from the wall when not in use (they use electricity even when the device isn't charging off them).
I can tell you that the qt tanks these fixtures are on are in my bungalow's dark basement. The heat generated from the bulbs does not negatively impact the water temperature under the conditions I'm using them in. Your mileage may vary.
