Re: differences between these two
Perhaps one of your friends had a bad experience with a student model Keilwerth or a Kohlert which sounds similar. Of the newer horns I have tried, they are my favorite hands down. The quality of the newer Selmers is not as good as the older Selmers, while their prices continue to soar. The Yanagisawas play nice, but I'm just not a big fan of their sound. The Keilwerth SX 90 is the most like the vintage saxophones in terms of sound and feel, with a better, modern action, and a few other advancements. The SX-90R has soldered on tone rings like the rolled tone holes on the vintage Conns. They sound a lot like an old Conn. They're German made, and the quality is better than any of the French Selmers I have tried.
Another suggestion if you're looking to save a few $$$ would be the Yamaha 62 series II or the 82Z. While they lack the vintage feel and sound of the Keilwerth, they play very well, and the quality is very good for the price.