i'm confused about all this paypal pro business

[testbot]

if i get paypal pro do my clients have to leave my site and go to paypal and then come back after the transaction is completed?

if not is it hard to setup?  it seems easy to setup just the button but i don't want our clients to leave our site.  it just seems unprofessional.

if so, what are our options?

thanks for your replies!!!

[testbot]

you people are awesome