The t5's are great. The ballast is built in so no need for a seperate one. This makes them very quiet. Also MUCH less heat to deal with. They also have switches on the side so you can turn some or all of the bulbs on.
We are talking 5000 lumens. With the t5's no extra ballast. Which means no noise. hardy any heat, you have the ability to adjust the light output. I have used both. I made the switch to the t5's about 6 months ago and have been very pleased with the results. Yes you can use the heavy duty extension cord and timer. Make sure that you are not overloading system.