[CentOS] Moving files to new server

Hello,

The new server is in and I am about to attempt the file transfers.  I have
NEVER attempted this and want to do it right the first time.

Reading the man pages for cp and scp it looks as if the -a switches are
different.  Are they?  I want/am going to transfer files/directories across
the local network.  Should I work from the new machine or the old?  What
files are machine dependent?  In other words, what files, if any, should not
be copied because of hardware differences?

Sorry for all the seemingly stupid questions but as I said, I have never
undertaken this before.

TIA