About as far as I have been is around 80yds , its a pain on retrieve if you dont wind in as soon as you hit the water , because the rear end dips under the water , but people I believe have stuck small pieces of buoyant foam in the rear as this solves the problem .
I dont use it in the winter as I tend to fish for one fish at a time , but in the summer I love the way you can spread the bait around , hit the clip lower to the water for a tighter spread ,higher for a larger spread .
I does take a while to get use to it and how best to use it , so its a bit of a learning curve to start with , but once you know what you are doing and what it is capable of IMO I think its brilliant.
120 yds I think is a big ask, and until I try it yonny is probably right .