I took my son, who was 5 at the time, to Babies R Us when I shopped for a new stroller for dd (2 1/2 at the time). That way I could see how the stroller would fit her a little older. In the Triumph, ds's head was above the back of the stroller. And the seat was a bit too shallow. (He was still under the size recommendations, btw). In the Quest, the
back of the stroller came higher than his neck (to about mid-head) and more of his thighs were on the seat. So we came home and ordered off the 'net one of last year's Quests.
Take your child to a Babies R Us and try the two out, do a little pushing around in the aisle. See which seems better for you!