Readie - 8:26 pm on Jul 12, 2013 (gmt 0)
The problem with using <? is there's a flag for it in the php.ini file which your server administrator needs to turn on for it to work. While your code works on your current box, if you change hosts or anything of the like, your code could just stop working.
For the sake of 3 additional keypresses each time you start a new file, you keep your code much more portable.