My question about the LEC possibly being the better choice is just opinions. I would think everyone would have said LEC.
That said, I've ran the
Mars Hydro 1200 in a 4x4 & it will veg the daylights out of anything you put in there. No complaints there.
If it flowered as well as it veg's it would be the only light you need if it's appropriate for the setup. But HPS just blows the doors off the 1200 in flower.
The 1200 though, I noticed stickier buds overall. But smaller, less dense. It's an awesome veg light. You could probably get away with the 1200 in a 5x5. The sides & corners would get noticeably less light. Ideally, you would want the 1600 for that. But the price to performance jump is not good. If i recall correctly, you could run two 1200's for relatively close to the cost for a single 1600.
I'm running a 600w MH in the 4x4 now, same draw as the 1200, but the 1200 seemed to do a better job.