The order of best modchips on the market* goes like this:
1) Wiikey
2) Wiinja Deluxe
3) Cyclowiz
It is important that you realise now that all three essentially do the same things, what differentiates their ranking status is the teams that are behind the chip. So far wiikey was the first to do everything, and other teams copied them. Not only this but they are the first to give you good programs** and firmware.
You really can't go wrong with any of the chips, but because of the team behind wiikey, you'd really be silly not to choose it. btw, like was stated earlier ensure you don't get a clone by looking at the official distributors on their webpage
* when i say "on the market" i don't include DIY modchips
** while its arguable their programs were already created before (emukids GCoS and SD Dumper were out before Wiikeys) the team puts it all on a nice and easy to use package.