The best lighting for your frag tank will be similar to the lighting you are using over your display. Otherwise you will lose time as your coral acclimates/adjusts going from one tank to the other.
Kind of depends what your purpose for a frag tank will be. Are you bringing frags into your system, or using it as a holding tank or grow out for sale or trade of frags from your system? If for incoming frags, I would definitely go with similar lighting to what you have in your display. For outgoing frags, I would go with whatever LED fixture fits your budget. They run cooler, easier on your electric bill than MH and you won't have to replace bulbs like T5s.
I chose the Evergrow fixture to use on my new frag tank, because I got it for $150 on eBay. At $150, I am not that concerned about getting them fixed. At that price, the fixture would pretty much be disposable if problems come up down the line. My tank will likely be for outgoing frags.