Getting tickets for the UK arena shows was really tough. They sold out super-fast. Wembley was a lot easier, because obviously there were a lot more ticket on sale.
I don't think many, if any, of the US dates sold out so you'll be fine.
I think it helped that there were big gaps between most of the gigs I went to. Enough time to get super-excited again. I think Reading was the most excited I've ever been for any gig in my life, knowing that I was about to experience OoS in full.
I plan on going to as many gigs as possible this tour, in the UK at least. Whether I spend money on travelling to see them abroad will depend on whether I love the new album enough to justify it. But I'm pretty confident that this album will be a return to form.
Be prepared for your first gig to be emotional. My first Muse gig certainly was. I was almost in tears when they came on stage (O2 November 09). But then I was the same at my sixth Muse gig. Dee3Dee can tell you how much of a fangirl I was that night
I went to six gigs on the last tour and don't regret any of them or any of the money I spent. I had a great time at all of them but there's no denying that they were repetitive and I would have had a better time with more setlists variation.