I really liked playing as spain and portugal. I think that they can have a bit of trouble in the early period because you get javelins, then amulgahvars which is annoying because u'd think an upgrade would get u some decent spear man or something...
but once u get going and get new lands.. Amulgavars on the walls are wicked because the javelins kill a lot when the enemy is in range and they can do well in melee. Also, putting ur javelins behind ur heavy infantry helps so that while the enemy's 3rd. 4th ranks are waiting to fight they are being hit with javelins while my heavy infantry is fighting their 1st-2nd line.
The both have jinettes and a good variety of horse/infantry and missile.