I have a 120mm fork on my 2015 Rockhopper. It is a Rockshox XC32. Heavy, but a pound lighter than the Suntour pogo stick that was stock.
I rode it at 100mm for a while then when the time came for its first service, I removed the travel spacer on the air spring shaft to increase it to 120mm. I weigh 220lbs and have had no handling or frame issue after nearly two years. Although it depends on how you ride. I have the bike set up singlespeed and only use it on tame trails for fitness, so little to no jumping or high speed rough sections.
One issue you may need to consider when shopping for a fork for your bike is the headtube. I think the Rockhopper Comp came with a tapered headtube, but you need to make sure. And even though it may be tapered, those Suntour forks had 1 1/8″ steerer tube. So you may have to purchase and install a new headset. At the minimum a new lower cup to accomodate a tapered steerer.