funny the OP mentioned the cs-450... thats the saw i have, and though i don't have a lot of experience with a ton of saws. it is by far the easiest to start i've come across. Several times i've had a 1 pull start from ice cold and if you are fast with shutting of the choke you can keep it running. i would say on average its 2 pulls to get it to "pop" or start running on choke. if it doesn't start running enough on 2 pulls to stay going, choke off and 1 more pull and you are good to go. I can't remember it ever taking more than 3 pulls to start cold. Once warm even after its sat a good while, 1 pull and you are running no problems.
To kick the thread in a different direction...what causes this ease of starting? The cs-450 does have a purge bulb which of course helps.