I like Lumatek. They are the most high tech digital ballasts that I have found, and I own 3 of them.
I will also say that I hate magnetic ballasts, for multiple reasons. They are electrically noisy. They do not produce a consistent output. They can not tune to your particular bulb's dynamics. They shorten the life of any bulb. They hum. They get hot.
My lumeteks are very efficient, electronically silent, produce light at 2400 hz vs 60 hz, therefore NO flicker. They can run either MH or HPS, with no adjustments needed. Oh, they also have a nice long warranty. They do not hum. They do not get hot.
I will never go back to magnetic... and as a Ham Radio operator, I demand electrically silent lighting. I got state of the art, because I know what I needed. Did you know that Lumatek's are also guaranteed not to be able to be sniffed out by RF sniffers?