Just upgraded my 17" MBP with a 512GB SSD - first impression is that it seems to have speeded up the system and made is v.smooth. Its a crucial memory M4 unit and was easy to install. I was thinking about diving in and buying a new retina MBP and sticking the 17" on EBAY but thought better of it and stuck in a new SSD Hard drive and it appears to have given a mid 2010 machine a new lease of life at least in the short term. I made the alterations via terminal to use the trim trim support - basically copied the commands from the internet, said a prayer and everything seems to work ok. Even my windows 7 programmes - Sage, TakeOff Live and Fast Estimate. This is my first Mac and though I've had it for 2 years now it still impresses - should have jumped ship years ago.