I don't have either one, but plan on buying a LFM-1 with a 990/7125 combo.
From what I read here, having 1 or 2 LFM-1 is better than having 1 or 2 LFM-2.
Also, two subs are harderd to balance in the room than just one, even though Outlaw says that they recomend 2 subs.