I'm running 10.8 on a 2011 MBP (sig), I'm reminded every week or so that Mavericks is a free upgrade. As it is with 4GB RAM and lots of spinning beach balls, I'm wondering if Mavericks has more or less overhead than it's predecessor. And is there something compelling I'm missing out on? And any incompatibilities I'm missing out on? 
Thanks!
Thanks!