It depends what sort of work you want to do. DS is more editing biased. For fx and design its a no-brainer. I would whole heartedly recommend learning inferno. In my limited experience with ds it seemed inferior in every way to discreets powerhouse box.
inferno is an awesome peice of equipment really the pinnacle of compositing in a lot of ways.
its real strength is it’s processing power and brilliant tool kit which includes the best tracker and keyer bar none on the market. coupled with an awesomely powerful 3d compositing environment camera tracking, editing and time remapping tools and soooo much more !
as for salaries. Well to start off take whatever you can get. Once you can use it then you can start making some REAL cash. Good inferno opps are worth an absolute packet and get treated very well by companies who want their skills.
And for god sake PLEASE tell me how you got so lucky as to be offered not just a chance at getting on the box but the choice !?!?!