So I have a mid 2012 MacBook Pro w/ Retina display 15", a solid 750 GB SSD, and a 2.7 GHz i7 Processor with a Turbo up to 3.7 GHz and 16 GB of RAM. When I decided to download El Capitan, I couldn't install it because I was formatted with MBR, thanks Windows. (Yes, I use Windows too) So I backed up both partitions with images, reformatted the entire disk, put the Mac image back on, hacked the windows image back on, but now I'm asking myself should I upgrade. I see the reviews average at best. Even if I didn't upgrade reformatting to use GUID was simply common sense, (I mean who uses MBR these days). Most people complain about the speed of the OS, or incompatibilities. So I ask those who upgraded, with similar tech specs, how do you like El Capitan? What are your problems and what do you like? For those with an older MacBook Pro with a standard HDD, how is El Capitan working for you?