Is 50% hike is too good? Just enough? Or should I get more?

This really depends upon the market value, and the value that you can bring about for the company (current which has given you the hike or the company that has offered the hike).

  1. Explore more offers before accepting or declining any offer
  2. Check what will be your new role. Are you ready for it? Can you even go for a role higher than that?
  3. Check the credibility of the company making the offer. Are they stable, or just aggressively hiring, but might fire later. For later, such a hike is not sustainable and career can then stagnant.

PS: Play ethically, avoid accepting offer and then declining at the last minute. Career is a long race, make sure to not mess-up relations anywhere as you negotiate