if you are going to be putting your helmet and jacket inside the case id go for a bigger case than the gobi. But i have just put my jacket in the case and locked my helmet on my bike. but if you need to keep it out of the weather then id say something bigger for sure.
i have fit my helmet inside, but that was it. arai xd
but other than that it is a great case. the bars on top make it so you can strap stuff on top and still have room for a passenger. and the back rest option is nice for that too.