I never really liked Massive much, but, Serum is alright really. Nice synth. Just too expensive, and, the no sales tactic doesn't help to boost my interest either.
It's really beyond me, once again, why such developers don't do sales. "I don't believe in sales" is kind of bullshit, when your synth doesn't sell much after 2 or 3 years, and you could sell 4 or 5 times as many copies, when you split the price in half.