Hey guys! I believe the Guild boss quest at 46 - 50 is Surbora.
With that said fluxedan
In addition to Jale Bandit Guild rep & Kaslow Bandit Guild rep & Bandit Badge for Ilya rep there is a hunting daily that you can complete too.
So yes it is a very fast way to gain experience and overall city rep. Umm, jelly crystal rep would be faster Jale-rep gaining overall (if you just want to get it for heavy arms specialist fast). After you've capped Jelly rep, doing Surbora on multiple channels (like Bryn said) will work fast!