Both Sensor and Big Game are reliable lines but they've both been round for 20+ years. There are lines available now that out-perform them in every way possible. They might cost an extra fiver/tenner but if there's one thing you shouldn't skimp on it's line.
Depends what you want it for buddy. Different mono's do different things better than others.
- For distance casting go for a pre-stretched line (e.g. Fox Exocet etc.). They cast fantastically but aint so good where abrasion resistance is required.
- For general angling without too much weed go for one of the new low stretch/partially pre-stretched lines (e.g. Shimano Technium, Gardner GT-HD etc.) These cast well and have half decent abrasions resistance.
- General angling in weedy situations go for an all-rounder (ESP Synchro, Gardner Pro etc.). Cast OK, nice and strong.
- Heavy weed go for a heavy line (Gardner hydroTuff, Rig Marole SLS etc.). Not so good for casting but you'd land a bus in a forest.
There's no such thing as a line that will do everything perfectly (although the low stretch options are getting there). Think about what's important to you and go for the most suitable.