If you are running an electronic ballast then I highly recommend the Digilux bulbs. I have tested them against other bulbs and used a light meter and found that they are worth a few extra bucks for what they put out. They last a long time before they begin to degrade, about 18months give or take. And they aren't super expensive. I also use the IPower bulbs and they work well but degrade faster and have lower initial lumens than the Digilux by about 15%.
However my testing was done a few years ago so all of that could be completely opposite by this point with the way technology and companies work. But I still like the Digis.