I look at this as a positive for two reasons :
1) The pay-once business model SL has been operating on forever has resulted in what we have right now : a stagnant software that doesn't really improve a whole lot with each patch, and key requested features are never implemented. So having this steady revenue stream should (I hope) result in better features.
2) A lot of centers (like Rsteele) think a monthly fee is unreasonable and won't pay it, and will instead find another software, or write their own. This increases the competition in the market, which is sorely needed. One of the main reasons SL has been top dog for so long, is that there are only like 3-4 dogs to choose from.