also i have the R.A.T 5 and i would recommend it to anyone, although if you are willing to spend a little more you could get either the M.M.O 7 or the R.A.T 7 infection, they both have a few more features that the normal R.A.T 3, 5, 7, 9 have.
theres not that much difference in the rat 7 to the rat 7 contagion to the rat 7 infection
the rat 7 to the contagion has a more sensitive eye and upgraded sensor with all the tiny benefits it brings. but nothing more... the rat 7 infection over the rat 7 contagion a fancy paint job, but still has the same problem of palm grease and finger grease laying on the mouse, requiring cleaning every 20 mins. its so bad i have had to aply my own grip coating to help me keep control of the polished enamel like surface.. both are over priced compared to the g400 or the roccat kone+ both 2 excellent mice for around £30 and both are much more reliable in build quality.
btw i have a rat 7 contagion, which also is supported on mac.
keyboard if you can do without the backlighting then the steelseries 6gv2 is the best keyboard currently out at the £65 price point. it out performs everything up to £90+ but is a little heavy on the keypress... 30+ ms x4 is ok better than most up to 50+ but lests face it if your gonna spend 50 but you dont wanna spend 100 you may as well spend the extra and get the mechanical 6gv2... which is more important, fast key response or pretty back lighting..