I left the hobby for 7 years and only got back into it in the last 12 months. on my return i had found that many things had changed and a new format had been created. Modern masters is a reprint set of the best of that format. many highly sought after cards as well as tournament staples are included within the set.
Wizards in their infinite wisdom decided to make several distinctions between this set and the others: 1. there was only one print run of this set 2. there is a premium card in every booster 3. being a set designed to draft with there are less boosters per box and each booster would be more expensive. 4. only bricks and mortar based retailers who were part of the wizards play network (and held regular tournaments) could get any.
The price of sealed booster boxes and the singles from this set will only increase as the product gets scarcer, my advice is to shop around if you want one but don't leave it too late.
Most of the cards in this set are amazing reprints of great cards, with a chance to get a great foil in every pack (24 foils per box) But these boxes are way overpriced and seriously - wait for these to go down in price first, they'll go down in price once the boxes individual card values drop.