Is it worth changing to T5's? Will I actually see a difference?

I have two 48" 110w URI VHO actinic lights supplementing 250w metal halides. The VHO's are driven by a pair of Fulham Work Horse Fluorescent Electronic Ballasts #WH5-120-L

If I read the specs right, that ballast will also drive a 48" 54w T5 bulb. If so, the only thing needed to change to T5's is endcaps and bulbs.

My tank is 24" deep and the bulbs are about 6" above the waterline.