The AI Vega's will cover a 24x24 area no problem. I am running the Sol's right now and covering that footprint without issues, and the guys and AI specifically said the design target for the Vega was a 24x24 area, so you can probably cover a slightly larger area with them.
I have been very happy with my Sol's - the one issue I had with them was a lack of a full spectrum (which was common when I bought mine). The Vega color addresses this issue. I''ll be upgrading mine through AI once they come out with the colored puck customizer (you can pick the color of the LED's in each puck, so you can fine tune the color to whatever you want it to be)
In your price range though, I'd definitely be looking at the Kessil's, the EcoTech Radion, and the AI Vega's