Pro/Con of enrolling a cell phone using wifi for calls

[Stewie]

I'm in limbo at my house for a decent cell phone signal. Sometimes it's decent, other times it's crap. I have the option of using my wifi to place/receive calls, etc..

I have a couple of questions.

If I use wifi at home will my phone work away from home like a normal cell phone? Will text messages come over wifi or are they still dependent on cell phone coverage?

Thanks for your help.