All my bikes have come with Metzlers, and every time I switched to another brand, I improved the handling. It feels, to me, as if they mismatch the shoulder profiles between front and rear. The last time I put tires on a couple of 80's vintage BMW K100's I went with the el cheapo Shinko Tourmaster 230 tires, and I was very impressed with the handling. They rolled off and onto center, deep into curves and back upright very smoothly.
One reason I went cheap, besides being a damn Yankee, is that I like the feeling new tires give. And, I'd rather change my tires more often than to try and coax old tires into a few more miles. BTW: Aramid belted tires do give a nice light feel, (it was as if the bike lost 50 pounds) but I did have one out of four that just could not be balanced. It was a bit of a hassle, but Shinko replaced the tire for free. I got mine at: 1.