I too enjoy this White Summit ride two weeks ago. Personally, it is worth every penny of it.
Our ship were late leaving two ports, so I think we made the right decision on booking through cruise because you just never know if the ship will arrive town on time or not.
I learned that every excursion in Alaska, you go through them, rain or shine. Consider yourself lucky if sun is out, but even luckier, if you just have light rain and not downpours.