Well, first I have to say that Superior has no idea what they are talking about and should not be spouting out false information when they clearly have no experience in this area. Please disregard what has been said so far.
There is actually a big difference in the 'normal' flourescent bulbs versus ones made for the plants/aquariums. It has to do with the phosphors used and where the color spectrum of the light is. 'Normal' lights are the 'warm' lights thats make everything have a yellowy 'warm' look to it. These bulbs are usually in the 2,500 K to 3,000 K color rating. Plant or aquarium bulbs come in lots of different rating, but most will try to mimic natural sunlight in some form or another. The higher the K (Kelvin) rating, the more 'white' the light looks to the human eye, but then, we don't see too many color spectrums too well. Many of the lights specific to growing plants actually 'look' lees bright because they are stronger in the red and blue color specturms were our eyes don't see too good. They are not as strong in the greens where our eyes tend to see the best. That is because plants don't use the green color spectrum much.
As far as advantages or disadvantages... kinda depends on what you are using the bulbs for. You didn't say what you would be using them for so kinda hard to answer that question. In aquaria, if you are growing plants in your tanks, then you will need bulbs with the correct color spectrums in order for the plants to grow. You will also need the proper amount of lighting as well. If you are not growing plants, then getting a bulb that looks good to you may be all that's important to you. In either case, I like bulbs with a 6,500 K to 8,500 K rating for both growing plants and making the fish's color's stand out more.
Hope that helps a little... if you can provide more info on what you are doing, we can be a lot more help!
Good luck,