Curious how you arrived at the Usher sw103? I know nothing about it myself. It just doesn't come up often
I auditioned a REL Britannia 3 and Martin Logan Abyss (and Dynamo) at a big box (magnolia) paired with sonus faber bkshelves. << I mention this because Mag is fairly common and allows you to audition one of the best subs around: REL.
I went with an Abyss (great sound and value vs. the REL). My sub is in a 2.1 with my Tetra120us (which is also part of a Denon/Tetra/Morel/MartinLogan 5.1 HT set up) But it's use is 80% 2.1 music.
Highly regarded music subs:
REL B-Series, Strata series
MJ Acoustics
Well regarded music subs:
Martin Logan Gratto, Dynamo, abyss,