reboot vs shutdown -r now for restarting Linux

I normally use reboot to restart my Linux box, but a friend said that I should use shutdown -r now instead. Is there any difference?

Looking at the man pages tells me something about run levels, but I'm hoping for an answer in simple English that a relatively inexperienced Linux user can understand.

Many Unix systems have reboot perform an instant reboot -- no syncing, no umounting, nothing. It's just like hitting the reset button.

Your friend is trying to save you hours of fscking, or worse, if you ever wish to reboot one of those systems.

There are likely slight differences in the functionality offered, but they can both be used to achieve the same thing. In fact, here's what the manual page for reboot says:

When called with --force or when in runlevel 0 or 6, this tool invokes the reboot(2) system call itself and directly reboots the system. Otherwise this simply invokes the shutdown(8) tool with the appropriate arguments.

Also, it appears that the RUN-LEVEL info for both operations is the same. Judging from the manual pages of both reboot and shutdown, it looks like shutdown provides a bit more lower-level functionality, and reboot is a higher-level tool that uses shutdown.