I personally don't (and didn't) think that pikkolo is that difficult to get on. I think if you've used a mei tai it's the same thing. I actually had an easier time with the pikkolo than getting dd into the infant insert in the beco.
Just wanted to add that if you get the pikkolo, I would really suggest you get the support belt with it. I just added mine and it took it to a new level of comfort. http://www.naturalmomresource.com/ was offering the support belt for free with the purchase of a pikkolo, not sure if that is still the case...
Never tried a calyx so I can't help there!