so i see a few sparkies have commented here, im a dual trade sparky, industrial and cert 4 plc. i cut ties by the 1000's week in week out, and the only 100% and time efficient tool is the marvel cutter.
Any beveled edge cutter will leave a point, the plier method takes too long, a knife will work well but again too slow for me.
this is my tool of the trade been using them for years!
http://www.marvelcorp.co.jp/global/nippers.html <- the top one is the cable tie cutter notice the flush cutting surface