Is it better to spend your time doing surveys or Mturk?

I have an Mturk account from a couple months back, but never really did any tasks.
I've done a couple surveys on my free time, but I don't go out of my way to spend a ton of time doing them, since I can fail some and lose the reward and time.
I'm just wondering if it'd be better worth my spare time to do surveys or Mturk to make more for my time spent.