I have used tubular track for a couple of years on the "non-clockwork" layout, and I became dissatisfied with the various track trips performance whether it was the Marx insulated rail, the Lionel spring contactors, etc. Several years ago I had more scale like layout and used Realtrax and still had a couple of tubs of track. I relaid all the track with Realtrax, got one of those Lionel infrared controllers and an unexpected benefit came out of it that might have to do with the railhead profile. What was immediately obvious was that the pulling power of whatever equipment I have was increased. Yes, the curve radius of 31 versus 27 does make some difference but not that much, and so I am wondering if anyone else has noticed this? I am thinking there is more contact surface on the rail. When I looked at the tubular profile, there was actually much less contact surface due to it's somewhat spherical shape. I had never considered any of this.
I also noticed less wheel slip when starting a heavier consist. For what it's worth. Also the power distribution seems smoother with less power feeds required.
I guess I am learning as I go along. Thanks for the thumbs up, those trains are now faster so I have to throttle back. Someone had asked me for an updated video of the layout with the Realtrax, and I thought what the heck, I'd post it here as well. The MTH track has a reputation for having finicky connections, but I found that tubular track needs clean pins, tight compression at the joints, etc. All of my track was used so it was a chore cleaning up and the MTH just needs a certain method to connect pieces, and I had long sections so it cut down on the connections. I wonder if Gargraves has a flat railhead profile? 
