i was looking into getting a giant squid lav mic. Which is a better choice?
: the powered or unpowered?

That would depend on what you are plugging it into, and how far you are running the cable. Ask Darrell.

the powered mic can do everything and more can't it?

I don't know to much about the giant squid mics, but I do know that a powered mike will allow you to-do more, now whether its powered by a battery near the mike or whether its phantom powered is where you run into other problems, usually phantom power will allow the mike to receive a much higher amount of volume rather than the battery. I could be wrong here but, I believe that if you use a powered mike, you can run the mike up to 50 ft, I've personally done 30ft. Anybody correct me if I am wrong.