re: Negotiating a raise. Edited for update

You should do what is best for you.

I don't know what your base salary is, but $50k increase in base pay is worth it even if you only stick around for a year or two.

Look at it this way. You can continue to work for your current employer or you can leave for 2 years and have an extra $100k and they'll probably take you back. If they don't, you still have an extra $100k and it sounds like you can find another job relatively easily.

Do it.