As Ralen mentioned above, exp does drop off considerably. Overseer becomes your best friend. Now, I did grind from 110-120 and I did it in GD Restless Assault. At 118ish I think I switched to ME Shei but you need to be SUPER geared for it. I was in full CoV T3/ToL T1 and would still get hammered on occasion due to the number of adds that can you have. They come out of the tile there, I swear.
I would spend time grabbing AA before trying to advance in level. AA is huge at 110+, same with gear. Work on it, then make the jump. At 115, you can get the ToL T1 gear, which is less than the CoV T3 until 118 when it breaks even, and then it is better at 120.