There are several questions going on here about that the last few months. You might want to do a search for them.
I don't know anything about the hardware, network, or other conditions at your office, but if you're having multiple crashes with SW2014, then I'd think it's unlikely to be better with SW2015. Many heavy SW users go days and weeks without crashing SW2015, and that was also the case with SW2014. I've been using SW since 2009, and I couldn't tell that SW2014 was any more unstable than any of the others.
I assume you've tried to find out why you're having so many crashes and freezes?
If you are finding stability is poor in SW14 (which SP ?), then it probably won't improve with SW15. Although oftentimes a clean uninstall & install with an updated graphics driver does fix stability & performance problems.
What are your system specs?
Are you all working over a network?
Are you using a PDM system?
Have you tried working with your VAR on the issue? Just like most things, if the foundation is not stable, the house won't be either. Like the others asked, what are you computer specs and how are you setup. More often than not, it is other issues not the software.