Well I'm a Front-End developer and my everyday software involves Photoshop, Illustrator, Sublime Text 3, Prepros, sometimes Github, Mamp Pro. I've upgraded to El Capitan and the couple of days I've been with it it hasn't improved that much in fact it kind of downgraded in transition and scroll "effects" in Sublime and Adobe, basically it slows down sometimes but just sometimes, specially when having two desktops and with a lot of software open. I hope this help you. I must say that I use a 27 inch iMac (3.2GHz Intel Core i5), 8 gb RAM and NVIDIA GeForce GT 755M 1024MB