Saitoh, he's cool... he and Kenshin still (as far as I've gotten) have yet to finish their fight. The Shinsen Gumi use a basic stance with variations and continue to use this stance even if it does not work - they are stubborn and will not stop until they win or die. Underneath all of the chill he puts out - he seems to care, but does not let it interfere with the task at hand. It will be very interesting to see what developes of him and the situation that Kenshin and Saitoh have, Sanosuke is also looking to fight him again as well, to prove his worth as a fighter.
I think he is an excellent character - as all of the characters go, Those brief moments when he does get caught off guard are great!!! - since he always seems so cold.