I have 3 of those bags - two of them are the regular burton wheelie gig bags, and I just bought the wheelie locker bag. The bags are very well made, durable, good padding, and high quality wheels. Weight is an issue but I like the wheelie bag much better than a light soft board bag.
To pack a 2nd board you need to take the bindings off of it and put it under a board with bindings.
When travelling alone I put two boards and 2 sets bindings plus helmet, boots, and all my other on the hill gear in one wheelie gig bag, and then pack a 2nd bag also with wheels with non-snowboarding clothes. Use a velcro strap to tie the board bag handle on the non wheeled end to the handle on top of the other bag in a train and it's really easy to get around airports.
When travelling with my wife and kids we I take 5 boards between 2 bags and pack as much other boarding stuff in with them, works quite well.