The Hydra or Vega's would be what I would consider if you are considering those 3. The AI Sol's use only royal blue, blue and cool whites. Granted, people have grown some great SPS tanks with the Sol's but many many many people gripe at the color they get from them and the intensity they provide. The consensus now is to use a much broader/fuller spectrum of LED's which the Hydra and Vega's use (Violets 400-420nm, reds (600-660nm), cyan, etc.). Plus the sols have very narrow optics by default.
If you are looking for good budget fixtures, consider looking at the Maxspect Razors for a little bit cheaper price than the Vega's with also a 'fuller' spectrum (assuming your 120 is 48 inches long, 2 of the 120 watt units would serve you well). You should also consider looking at the reefbreeder full spectrum lights as I have heard great stuff out of them as well (they are also a lot cheaper than the Vega's/Hydras although not as aesthetically pleasing imo but will definitely get the job done).
I use 2 of the 120 watt Maxspect Razors over my 90 and have had good results (using for the last 8 months).