biannuzzi22 - I have some experience with the SS1 and SS2. Repair is an issue, I haven't found schematics yet. Low-level noise is an issue; if you need black quiet, maybe not. Performance is unique; the user has no control over amplitude. Jim's gig was to play back what's recorded. Some folks want more bass, which you can get by messing with the room boundary controls. The room boundary compensation really works. With the PXO, the main speakers work as hard as if solo, so you won't gain additional output capability.
I find their performance outstanding with the Passive OXs. I'm told that the active integrator is another league up. Biggest gains are with the smaller models having less extended bass. The 2.7 will get only a final bottom fundamental - surprisingly little content, but surprisingly satisfying musically.
As previously discussed in this forum, I really like stereo subs. We're not supposed to have directionality at those very low frequencies, but a pair sounds somehow more real (for only twice the price!). If solo, try to get it near the center. I use the subs with dynamic, big music and turn it off for solo and small ensemble vocal which has little to no sub bass, and the quiet is nice.