The difference between CFL and Flourescent

I was just curious as I see so many posts on CFL lights, which are just the little twisted flourescents correct? What is the advantages of those over say two four foot strip flourescents? Is it a Lumens thing (do they put off more light)? or is it a spectrum thing (better colors for the plants)?

I am asking because I have done many grows with regular flourescent lights, but the plants looked nothing like some of the monsters I have seen on this site grown with CFLs.

CFLs ouput WAY more lumens per watt than regular tube flourescents. CFLs aren't the best lights you can get, but you will definately be happier with them.