Michellin Pilot road 3 trail are one of the the current big sellers for adventure bikes and come with a free £25 fuel card this month. Quite a few threads of late so do a search...the link i posted above will give you a rough idea of prices fitted to loose wheels.
I had a pair of PR3s on my old Kawasaki Versys. They warm up quickly and you can treat wet roads like they're dry. If you are committed and brain-out (or in a panic emergency situation), they'll get you through.
Before the PR3s I had the OEM Dunlops and they had terrible ultimate grip, particularly in the wet, but when they did reach the limits, you could feel the tyre letting go. On slippy corners you could feel the grip going, drop it in another couple of degrees and it would scrabble, vibrate and shimmy though to the other side and you'd still end up roughly where you wanted to be on the exit.
The PR3s had FAR more grip and it was very hard to get them to let go, but grip was all or nothing. In the few times I accidentally got the front to slide on a roundabout, it was a half-metre side step and a proper brown trousers moment. If the rear stepped out, it slapped you on the return stroke. I never got any feel for when I was reaching the edge of adhesion. Maybe it's a Versys (or me) specific thing???
Also, the PR3 is very stiff (probably the reason they are all-or-nothing on the grip front), so you feel every wrinkle in the road. The Versys doesn't have the most supple suspension available, so again it might not be an issue on the GS...
