I use Phantom ballasts, I got 8 of them and they run great. I guess the only diff between the two ballasts is
lumatek has a built in fan, phantom doesn't use one. Some like it some don't . The people that don't like it say it because the fan breaks and also allows dirt and dust in your ballast.
Phantom ballasts can stand up vertically or lay horizontal . So you can mount them how ever you like. Phantom Ballast literally stand up on their own.
Phantom also has a "soft start" on their ballasts.. Which is pretty cool..
I'm not telling you what to pick , pick whatever you want. But i got 8 and i like them they run quiet as fuck. (no fan noise) . Also their dimable . You can use it at 60,75,100%