What type of water will you be fishing? A 4 wt is good for small to intermediate sized waters, but you might want something a bit heavier for larger waters/currents and the possibility of getting into big fish.
I'm a big St. Croix fan, so you won't get any arguements from me. If you weren't doing a catalog order, I'd say cast before you buy to make sure the rod is right for you. In fact, if you know someone who has one of the rods you mentioned, give it a test run if at all possible.