Is it still worth upgrading to mountain lion or should i just wait for the next one?
I'm currently on Lion and am pretty happy with it so far but don't want to get too many versions behind in case of potential tricky upgrade paths.
In my opinion, Mountain Lion is a lot better than Lion in many ways, i.e. for me it is faster, smoother, is better on RAM, has useful features like Notification Center, Notes, Reminders etc.
If your Mac supports Mountain Lion I would upgrade if I were you... but wait and see if it's supported by 10.9 first. If it is, you may want to upgrade to it. If isn't, then you should probably upgrade to Mountain Lion at some point in the near future. (I think you will be pleasantly surprised about the improvements made over lion
)