The rate is higher if ordering online, then you can use a CC with the best rewards so those do add up. I just cashed in some CC rewards (used that card to buy Disney gift cards among other things) for a Carnival GC to go towards our cruise.
As the MB issue-it usually is just a few hour issue-like it is usually up and running within a few hours. I wouldn't be afraid to use the MB if you want to pay. In all our onsite trips only once was there an issue with the system being down.
On another note-DD managed to trade shifts on August 5th-so she booked us the Wild Africa Trek!!! So dang excited!! With the astounding CM offer we got all 3 of us for the cost of paying for one regular price!!! I'm too much of a cheapskate to ever pay regular price so this is great for me

And a great 25th anniversary present to ourselves.
Have a great time! we love Blizzard Beach, but I think we are going to go back to Typhoon Lagoon this time as it has been a few years since we've been. Have free tickets to use. Would love to try Volcano Bay, but free vs paying for water park-cheapskate comes through again