The rear caliper is a lot easier to maintain than the front one's, push the pots out a little bit and give them a good scrub with a toothbrush and a can of brake cleaner. If there's any visible rust spots, try and remove them with a bit of wet n dry paper.
Don't use any other similar degreasing sprays because they have different ingredients which can leave an unwanted residue which can actually cause the pots to seize.
When the pots are clean, check they are moving in and out okay, then you need to cover the exposed outer part of the pots with red rubber grease, which you can get cheaply off Ebay in small tubs, or even sachets.
Don't buy the 500g tub, unless you're planning on doing a few hundred bikes, 50g will last you a long time.
Then wire wool your caliper pins and lightly smear with a bit of copper grease, another must have, especially when putting any bolts back on, a bit of copper grease on a bolt can save you the agony of seizing in the future.
Light smear of copper grease on the back of your pads then job's a good'un.
I have noticed in the past that some pads create more brake dust than others, namely EBC, so i stopped using them for that very reason alone.
When these brakes are functioning properly they work extremely well, and there really is no need to look elsewhere!
Another small thing that is overlooked and can make a noticeable difference is dirt that collects inside the joint of the foot brake lever, especially if your bike is left out in the elements.
Give the joint a spray with degreaser, or even WD40, or both, then lube it with 3 in 1 oil.
It really makes a difference, i clean mine every 2 months just to keep it sharp.