One thing for certain, you will want to speak and read Spanish when living there...
I've been reading and researching Panama for a while now, since I was there in 2010. Lots to learn, lots of opinions from expats in forums like this one.
One thing keeps coming up in all of my reading and discussions with folks who have done this, you need to be flexible.
X2, the ability to converse and understand a conversation goes a long way towards a more satisfactory and pleasant experience. Otherwise one tends to isolate or associate with only other expats and misses the best parts of another culture.