I haven't used them, but I'm strongly considering the related Falken Ziex ZE950.
As Rand said, the Pro G4 is a rebranded Sumitomo HTR AS P02, which in turn is a slightly modified Falken Ziex ZE950. According to Discount Tire, the Pro G4/HTR P02 has more siping than the ZE950.
In my size, the Pro G4 is H-rated, the P02 is V-rated, and the ZE950 is W-rated.
All three have a 65k warranty with the H or V speed rating, and 45k for the W-rated versions.