Local Install and Upload

Hi,
I have seen similar questions like this but just want to double check before I do it. I already have a wordpress site up and running through my host. I want to have another wordpress install running that I can use to test new themes and work on as a test site. I know I can install in another folder on the current site and do this (which I do like because I can edit from any computer) but I was thinking of installing it locally on my windows PC.

My questions are 1) Is one way better than the other…installing it locally or installing another copy of wordpress in another folder on current site?

2) If I install locally, is the transfer/upload process to make it live on my current site easy enough? Is it basically the same as if I had it installed in another folder on current site?

Thanks
Chris