I will miss Green Ronin's products, some of which I liked.
I'll probably still buy system-neutral Freeport stuff, but that's about it. I have no real interest in Blue Rose, True 20, or Mutants & Masterminds. It's disappointing to see GR choose to abandon the majority of their customer base.
I guess supporting their mini-systems is in their best interest, but I would have liked to have seen their efforts at creating interesting subsystems for the GSL akin to the good ones they put out for the d20 STL, like The Black Company Campaign Setting, the Thieves' World stuff, and other similar products.
But I guess they have to do what makes sense to them. I wish them luck. Hopefully the market is big enough to support them.