I use and am happy with 685mm Easton bars and a 70mm stem on my Blur LT2.
I want some new bars due to a bit of damage and was toying with something wider, what can I expect from some wider bars, is there some benefit above and beyond comfort?

Stability going downhill and power steering through technical sections.

once you go wide you wont go back
780mm here and loving it

Personally I think it depends on a number of factors, firstly if you are a DH rider riding serious technical terrain then yes they make a big difference but also your build and the width between your shoulders also need consideration. Slim people suit narrower bars bigger built people can get away with wider bars than slim xc jeyboys like me…

Have you got a buddy who can let you try some wider bars? Are they for a trail bike?

Don’t forget you may also need to change the stem if you go wider to compensate for the extra width.

Yeah a trail bike, just dicking about in the woods around Surrey mostly & trips to Wales etc etc. I am a larger chap for sure. I think 785 would be catching on trees and all sorts I was thinking more 730 ish…

730 sounds bang on for trails/local stuff.

I have got 720’s on my bikes but would love to go wider. 720 is the max I can get away with on the local forest trails.

was thinking of getting a wide Superstar one and keep cutting it down until I find my ideal width. for non forest/local riding.

I’ve got some Renthal fatbars cut to 740 fs soon – riser version. Mail in profile if you want/interested

Yeah could well be depends how soon, will mail in morning.

A lot depends on your shoulder width, bars should match to give a comfortable riding position. Wider bars will force you over the front more by bringing your stance forward, more stable for turning but going too wide can work against you in the rough stuff as your elbows will be constantly bent. A shorter stem will help as it will force you back and bring in your center of gravity.

Testing is the only way.