I don''t have any hair raising tales to tell, but my experience with the bosuns chair and the ATN type climber, leave no doubt that the climber is the ONLY way to go aloft. (my english teacher would roll over in her grave if she read that looong sentence!)
The climber gives YOU complete control of your ascent and descent. It allows you to proceed at your own pace and physical ability.
As to working on the front of the mast when climbing from the aft side...I''ve never had a problem. At the top of the mast you can easily work on both sides and reach around to the front. I''ve always understood that it was bad practice to use any halyard other than one through a sheeve as the bail/swivel could fail and ruin your whole day.
My climber is a copy of the ATN. I used my old bosuns chair (with a lap belt to keep it strapped to my butt) and two ascenders purchased from a mountain climbing supply co. I fabricated the foot straps from some 2" webbing on my sewing machine and it works great!
The ability to go up and down the mast without being dependent on anyone is a BIG plus!
The climber wins hands down in my book!