Tom- I've had both types of systems running at the same time, one at home, and one at work. My 300B SET's are my amp of choice, and have been for some time. Power's never been an issue for me with LaScala's. If you've been listening to SET for that long I sure don't need to tell you about it's strong points. The only thing that push/pull will offer that is different, at least in my experience, is the ability to handle more complex, layered, textured, and or dynamic music, with aplomb. As far as anything else you are likely to listen to, I think you would regret the decision if your priorities lie there. You will loose be loosing a large part of the airiness and holography that SET does so well and so distinctively. I've been more intrigued to hear some of the better OTL designs (Berning, Atma-Sphere) to see what they may have to offer, but that is an expensive endeavor and requires some careful component matching (as does SET). If you are intrigued by P/P why not test the water in a more moderate, less permanent way? A pair of Quicksilver MiniMites can be had for around $700 or less on the used market. Damn fine little amps, and you can sell'em for what you paid for them with no effort too if you don't like them. They will give you a very fine taste of what P/P can do.
Marco
Marco