Monthly subs usually just mean pay-by-the-month, but you are locked into it for twelve months - which means you can't just opt out for a month, you still pay for the month that you go on vacation.
You are still supporting Scirra (the great tool builder^^) that now, with this model, can work faster, better and more efficient. Win for you ^^
More features and bug fixes when you get back from holiday ^^