Subwoofers - Front Firing or Down Firing - Which Sounds Best?


Any advantage to woofer cone facing toward listener as opposed to firing down to the floor? Thinking of upgrading my 20 year old B&W ASW-650 sub to get that oh-so-pleasing belly message which lives in the 20-ish Hz range (very rare I know). SVS has the "tube" subwoofer (PC-2000) at a reasonable price. Just wondering if the floor-firing model would disappoint? Wouldn't want the hassle of returning if it did. Any opinions? Current users? Thanks. 
128x128dweller
Syzygy subs, fires front or down, your choice, control from your seat, and EQ. Sealed and fast. 
i found that the direction the driver aims has an impact on the quality of the bass.  front facing subs, in my room, projected and distributed the impactful, tight bass out into the listening area the best.  
some people even adjust the angle of the axis to get the best results. 

Here you go:

http://usr.audioasylum.com/images/0/4120/Me___HQD.jpg

Get yourself a couple of Hartley 24" subs and you will have all the bass you need, I would guess...

Cheers!

(Full disclosure:  We made some cabs for these back in the day..not the ones in the pics.  Ours were about 5.5' high and weighed in about about 200 lbs each...they were tanks!)
I like the design of the REL subwoofers.  Rythmik would also be another option.  However, no dealers carry them to listen to them.
I know the experts say it ain't so but my old mirage with 2 opposite side firing woofers does a really good job without needing any room correction software. That said I needed a sub to double as an end table in the family room and bought an entry level paradigm 15" with arc that doesn't draw to much attention to itself.