Downfiring vs front firing subwoofer

Okay.. I have seen several threads on subwoofers comparing downfiring vs front firing subs. I notice that Axiom uses front firing subs and HSU, Outlaw, SVS (all subs highly recommended) use down-firing subs.

Wouldn't down-firing subs sound completely different on different surfaces? What about a cut bur-bur carpet vs a wood floor? What are people's thoughts here?

I notice one of the SVS subs has a platform it sits on,
http://www.svsubwoofers.com/subs_pb12_isd.htm

But they also make one that appears to be front-firing:
http://www.svsubwoofers.com/subs_pb10_isd.htm

Can anyone comment on how these compare to the HSU VTF-MK2 ($500) or the Outlaw LFM-1 ($579)

http://www.hsustore.com/vtf2.html

http://www.outlawaudio.com/products/lfm1.html

Or.. compare them against any of the Axiom subwoofers, which appear to be front firing.

I really like my Mirage subwoofer. It is a "bi-polar" design utilizing two 10" woofers firing out of either side. I'm not sure how much different a subwoofer would sound firing directly onto different surfaces. I would think that it may affect the loading of the driver slightly. My preference leans toward the front or side firing subs. Even the single driver Mirage subs are front mounted.

A couple thoughts. . .

The material of the floor can change the sound. Hsu tells you to put a throw rug underneath the sub if you are on non carpeted floors. Also Hsu's new sub is going to be side firing instead of down firing. . .

All the subs mentioned receive high praise, it comes down to how much you can spend, WAF if applicable and what looks better in your home theater.

The biggest benefit of downfiring sub like HSU is that it survives small kids approaching within touching distance. If this is not a concern just pick the one that you can afford. Personally I would bite the bullet and get Axiom 500 for its smarts.
I have a HSU STF-2 and were it firing down it would have been destroyed a few times already over the last year. Kids are just too curious.

while waiting for the ht room to be done, my hsu was upstairs on hardwood.

Not a big difference in overall sound vs my new carpet. Part of the reason why they you to put something under the hsu is because the legs are extremely sharp, and with the weight of these hsu's, they'll even pearce some carpet rugs so beware on hardwood. I stuck 4 pennies under my legs, and it worked fine.

Not to mention cheap

Bottom firing, side firing, doesn't matter. If you like to see your woofer or hide it away from kids and careless people should be considered more imho. Some say that down firing has more options to where you can place it in the room....not sure how much truth there is to it. Ask Craigsub

Yeah, Steve, pennies under the legs are cheap, but I recall reading of an audiophile who "upgraded" from pennies to nickels and found his bass to be tighter and a half octave deeper.

Wouldn't it make it five times deeper?

I was thinking that JohnK, Alan, and others have claimed that subs are NOT directional in sounding, especially for around 80hz and below, so it should not matter if you have the sub pointing up/down or whatever. There is some fact in placement away from back/side walls improve the overall experience, but it is not required for you to aim the sub right at the listening area.

Axiomites, correct me if I'm wrong

I used a Home Depot carpet sample, I think it was 2.99 or so. Fits the size perfectly and improves the bass...uhm...299 times?

In reply to:
There is some fact in placement away from back/side walls improve the overall experience, but it is not required for you to aim the sub right at the listening area.

The biggest effect is definitely placement against a wall or two (corner). If a sub has enough power, it should be away from the walls to make it easier to "dial in". This has the unfortunate effect of reducing the WAF. A smaller sub placed against a wall or in a corner benefits from the "extra energy" produced from reflections. I believe this can make it more difficult to sound good and may require strategically placed bass traps.

You are correct in your statement of not requireing to aim the sub.