I have about 400 feet of track. 90% is Gargraves Flex-Track with lots of free-flowing sweeping curves. The only exceptions are the switches (Ross) and a couple of return loops using GG sectional track where I wanted the loops to be perfectly circular and concentric.
As said elsewhere, bending flex-track beyond a 54" or so diameter is tough but doable if you take your time. Also a pain is getting the flex-track sections to form smooth connections, especially when the sections join on a curve since the inner rail will extend and the outside rail will shorten.
