Hello, Ernie.
I have not heard the aluminum cone, but I do own a single F12G. I think it is a tremendously good sub and a great deal for the price. As good as it is and as good as it sounds, I personally think you will be happier with two of them (or more if you subscribe to the Swarm theory). I've used mine in three rooms - ~15'L X 12'W X 8.5'H, 13.5' X 29' X 8.5', and a huge cathedral ceiling family room/kitchen/breakfast nook.
No time to finish....will add later...
Okay, more time now.
In the smallest room there was never any doubt that one sub was enough. The room was filled with low Hz bass in a very pleasing way.
In the cavernous family room, I struggled to find an ideal location for just one sub. There were just too many cubic ft of open space to fill. It wasnt the sub's fault because I never got my L/R speaker to sound very good there either. I suspect my family room was deliberately designed to be the 'acoustic room from Hell'. The architect ought to be shot. I briefly tried using two subs (an F12G and a PSB 12" sub) and realized even this was inadequate. My wife wasn't quite ready for a subwoofer swarm invasion, so I never pursued multiple subs in that room. The only speaker that sounded 'right' in this room was my Ancora CC.
In my 13.5' X 29' room (formal living room/dining room), the single F12G was adequate, but everything sounded better when I added the PSB sub. My two-channel system sounds best in this space.
Three things kept me from running out to buy a second F12G: my deciding I 'had to' get a pair of the Rythmik double eight subs (increased WAF appeal), but never happened due to unfortunate investment decision; my relocating to Taiwan for 6 months (had planned to buy a pair of double eights for Taiwan until I discovered the 21% import duty!), and my 'discovering' the GR Research OB sub sound at Captainhemo's (Jay) home - six hours of wonderful music, food and conversation. Simply magical.
So do consider buying two F12G subs, but start with one. Perhaps I could sell you mine down the road once my future living location is clearer.
Michael