Hey everyone,
Ive spent many weeks over the years in both places and can whole-heartedly suggest - Do it!
In the interests of full disclosure you should know I run tours to Mauritius, and my good friend runs Zephyr Kite tours to Cocos islands so I"m biased to these places.
Regarding, the whole "refugees flooding Cocos Islands and making it a bad place to be" - Bollocks! My ole mate and original founder of Kitethrills is co-managing the pub/club/cyclone shelter on West island where the refugees are processed and there is no problem - they are all moved on very quickly and it makes no difference to tourists.
Regarding wind - Mauritius and Cocos are very similar - Indian Ocean winter trade winds are the most reliable and consistent. well more so than the pacific winds anyway. Both places can have weaker winds, but they are both still more likely to blow than anywhere else.
The main differences between them are the water conditions, and the cultural experiences.
Water conditions in Cocos are stunningly beautiful coral atoll with internal lagoon of white sandy beaches, warm shallow aqua water.
Water conditions In Mauritius: a flat water lagoon inside a fringing reef that has wave riding on the outside.
Cultural Experience - Cocos is awesome laid back Aussie comforts with twists at every turn - tiny island population antics, attitudes and love of life that leaves you smiling. Mauritius: hugely culturally diverse, with African creole, English, Portuguese, Indian, and French influences. The language barrier is not a significant one that will affect you. Everyone speaks English.
The bigger population and land area on Mauritius results in more "extra-curricular" activities, but really this isn't a huge differences for kiters as usually there are only one or two days any fortnight without wind and there are more then enough "other" activities on cocos to see you through the still days. if you travel with no-kiters then perhaps this might be significant - markets, zoos, clubs, waterfall walks, canyoning, dolphin swims, yacht sailing, etc may appeal.
Both Cocos and Mauritius are fantastic holidays and everyone should do both at some stage.
Mauritius has amazing waves sure, but the really special bit is that you can ride cross offshore waves, in good safety which is a rare opportunity. Cross Offshore waves are so nice to ride as they are clean, bump free faces, and the kite can sit almost still no matter how many top turns you get on the ride. They are hero waves making any rider feel like a superhero.
Its rare to have this set up without fear of being blown out to sea. No matter what the set up - beach or reef, a safety boat and back up support is highly recommended. This is where the Kitethrills Mauritius Tours give great value. You can ride these rare conditions without exorbitant fees to a boat driver to watch you - we group the cost of boat support to make it affordable. As an extra service we have pro photo and video operators capturing the moments you feel like a superhero, and we have video coaching clinics in the evenings.
The cocos is a great place for beginners to learn the sport - Zephyr has an in-house school and operates a great personalised service. Go for 10 days and come home a kiter.
Kitethrills doesn't run a school in Mauritius however there is s agreat beginner bay and a bunch of school competing for your dollar. It gets a little crowded in the beginner bay but there is the opportunity for our boat to take you upwind with your instructor away from the rabble.
the group tour options the we and Zephyr offer are great as they package otherwise expensive items with bulk purchasing and give greater service at the same price that you would get if you did it all yourself. Also, ive enjoyed watching dozens of friendships develop over time between people who meet on the group tour holidays on Cocos and Mauritius. You cant put a price on friendships

In Mauritius, the boat support is kind of essential if you want to fully enjoy the unique opportunity of riding the waves of the outer reef. If you tangle break a line or the wind drops and your 1km offshore, its kind of nerve wracking to rely on a fisherman to see you, come and get you and charge you 100euro or more to save you - I hope he's not having his day off while i drift the deep blue on my way to Africa. It sounds alarmist but each year people are lost at sea in Le Morne. We have a spotters on the beach, in our boat, and our staff on the water all with radios to ensure you get picked up pronto.
With the Cocos, the group tours offer an awesome beach shelter area, services such as spares and demo gear, the pick of the island accommodation ( this year there is a new runway being built and workers are filling the accommodation - there isnt any spare) The Zephyr tours have got the problem solved for you. Also they run an awesome social calendar to keep you on your toes and smiling.
As i said - do both AT LEAST once!
Wow - sorry for the essay.