Done a fair bit of Radio Tower climbing myself, in my fitter days, mostly in the UK, although my worst memory was climbs in Moscow, Ostankino TV Tower, the towers 540m (1770 ft) in height, scary as hell, not because of the height but due to complete lack of ongoing maintenance of the thing, loose bolts, flexing booms and bits of unsecured heavy duty cable flying around doing its best to squash your fingers or push you off balance. As for the Russian Riggers not even going to go there.
Most Towers or Mast in the UK are no longer Free Climbed, but have a Rail Lock system in place whilst climbing, a sort of vertical Man Safe system, although theres still a few riggers that dont use them because its time consuming, the going up and down bit is the easy part, the dodgy part is then having to free climb outwards to another leg or something then strapping your belt lanyard to something so you can hang off with both hands free to do the required work.
My pet hates were low level Guyed Masts, up to 100ft, they had to be built and climbed whilst building them so your life really was in the hands of the Guy on the ground who was tensioning the Guy Wire as it was being built.
Happy Days

Chris.