I know, you've heard that before, but really, you will probably end up with both. I have medium hands and like both handle styles, but I really prefer the regular style, it just fits my hand better. Also I like the bigger belly on the regular for most of the work/cutting that I use this knife for. The classic is to pointy for me. I also noticed that the lock cut-out on the classic would bite my finger (it is just a sharp corner) when I choked up on it. I'm sure that the new ones are chamfered, mine is an old one without the pocket clip recess. Your mileage may vary, see if you can handle both of them and make your decision. Either way, you can't lose.
As far as switching blades...did not work on mine. Although the lock-up on the regular handle with classic blade was stout, the point did protrude in the closed position enough to advise not doing it. In the classic handle and regular blade configuration...lock up was very poor. That's because each knife is fitted to "itself".
