Another Update:
Now pushing about 30 months and over 43,000 miles and they are still going strong. Very even wear on the rears which are getting to the wear strip. Fronts can definitely go longer. Couldn't be happier. Will absolutely buy these again!

 

I have had the GMAX on my XF for almost 2years, they have been great!

 

Just read the center rib on the tire when in doubt.. it actually says "replace tire".. LOL. I've been running them at 36 psi and noted a little more center wear overall..

 

The General G-Max finally **** the bed. Both rears were smooth and cleanly worn straight across, so the adj. cambers did their job well. The fronts showed a little cupping on the inside of both and a little more wear then rest of tire. Got nearly 44,000 out of them so I consider them golden. So now she's panted with new G-Maxs (235/40-18, 275/35-19) as before. Rear align was spot on and taking her in Monday for install of alignment bolts to fix the cupping up front. $770 shipped from TireRack. Very impressive shipping...ordered noonish Wednesday. Rears from Georgia whse arrived Thursday; Fronts shipped from Louisiana whse arrived Friday. Installed Saturday.

 

I've had mine for about a year now, and I'm very happy with the ride and durability.