Need a new subwoofer

[thedude65]

I currently have an 11 yr old klipsch ksw200 12" down-firing ported 200w sub rated down to 28hz. always did a good job for HT but lacked a little with music accuracy (set with radio shack spl meter). does a closed-box sub have an advantage when i comes to music or overall reproduction? Which is considered better- acoustic-suspension(closed) or bass-reflex(ported)? The B&W asw700(10'',500w,closed,22hz) or 750(12',1000w,closed,20hz) , Axiom EP350-v3(12",300w,ported,18hz) , and HSU RESERCH VTF3-MK3(12",350w,18hz) have all caught my eye. Also, when it comes to side- firing or down- firing, is one better than the other, and for what reasons? Looking for recommendations. Thanks!