The "Best" mod chip is purely down to preference...
I was torn between the Wiikey & Cyclowiz
but I'm going to go for the Wiikey... why?
well because I dont need a switch(or two wires sticking out the back) to update the Wiikey... which you do for the cyclowiz (last I checked)
So i'm going to go for Mr Wiikey
your best bet is to read up lots and make sure its what you want to do...