Last month I swopped my GS twin cam (2011 triple black) and S1000XR (2015 SE) for a new 2018 GS.
GS Triple Black tyres:
supplied new with Tourance, didn't suit sporty road riding, lasted 6250 miles;
Roadsmart 2 on the road much better in every respect, replaced after 5000 as needed dual purpose tyre;
Trailmax, fitted for trip to Morocco, great off but not good on road, 7000 miles;
T Next good compromise, lasted 6000 miles; and
Roadsmart 3, brilliant road tyre, still on bike when sold (done 3000 miles).
S1000XR tyres:
supplied with Pirelli Diablo, superb but lasted less than 2500;
Pirelli P4 not suited to the bike, lasted 5000;
Roadtec01 excellent all round still on bike when sold (done 2000 miles).
2018 GS
Supplied with Anakee IIIs. 'Oh no' I said to the salesman having read some negative views here on them. 'You haven't tried them yet' he replied. And he was right. I am very pleased with the IIIs. They work extremely well in all conditions and seem admirably suited to the GS (which no doubt BMW considered when fitting them). Better than the T Next? For me, yes, as more sporty and agile than I remember T Next to have been.
It must be said though, that most modern tyres are so accomplished that for much of the time there is little to chose between them. The choice, it seems to me, comes mainly in regard to what off-road ability is required. The IIIs seem fine 'on light trails ... over most surfaces' other than mud (MCN Tyre Guide 2016), the T Next look a bit less able on the road but a little better off-road. For me and most other GS riders the bike will rarely if ever go off-road so we delve into detail, price and appearance to decide which sport touring tyre suits best.
We all seem to have our favourite brands and engage in detailed analysis and comment, much like wine 'experts', and we lap up test reports on stopping distance and relative lap times and so on. So, despite the plaudits handed out to the P4 and 01, I think I'll replace the IIIs with Roadsmarts, providing nothing better has come along of course.