Actually you cannot generlise. Some versions of Chrome may be faster and
vice versa. In independent tests recent versions of FF are faster, but it
is a quickly changing situation with a nrw version of FF out each month and
Chrome changing almost as fast.

As for bookmarks, if it is an older version of FF then it is already an
html file (bookmarks.html). More recent versions use a database and you
must import the bookmarks. As long as you have your bookmarks.html file
then you are okay. The trick is to locate it in its hidden folder and to
store it in a safe place until it is time to upgrade and then to import it
into the new version of FF.

As already mentioned an alternative is to use a web service such as Xmarks
to sync your bookmarks across computers.