I just rode a Phil 18t cog for the first time today...
I wanted an all new drivetrain on my beater so it's a:
Campy C-Record track crank (170mm)
HKK Vertex chain (silver)
Phil 18t cog
TA Specialities 44t chainring
Phil bottom bracket

Dude, this stuff ROCKS!
This gearing is perfect for the hills of SF.......
44/18 and yeah you spin a bit on the flats BUT ...it's a City ! and you never REALLY get to mash...
It's all stoplights, pedestrians, pigeons, and potholes..