I have been using a pair of CSW Model Sixes forever as my fronts, with 17s as rears. They sound surprisingly good to my ear (not an audiophile, but I do home recording as a hobby, and have done a few demo recordings or friends, so my ears aren't completely useless). Their main flaw is I need to set the crossover to the sub at around 120Hz, which causes a bit of directionality to the low end. This is with the speakers flush to the wall (the corners are inaccessible, long story).
I see rave reviews on the SP-FS52-LRs, and I can go pick up pair for $89 each+tax right now should I so desire. I do not have money burning a hole in my pocket, so the question is: are these now discontinued towers a significant step up over the old bookshelf speakers?