Is it better to hold funds in Bitcoin or Monero?

Is it better to hold funds in Bitcoin or Monero?

I was wondering this because Monero is preferable to Bitcoin in its usage for me.
Monero seems to be everything that Bitcoin was suppose to be but isn't; its less traceable, it provides better anonymity, and is open in that we know the creator/s.
However Bitcoin is a lot more developed, and mainstream.
Does this mean that Bitcoin is a better currency to hold funds in or should I transfer all my funds to Monero?

Also would I make up the cost of my transfer funds?