Difficult to say.
Swisschamp has it all, but it is so large that it is difficult to use and clean it.
Picknicker has long blade and works perfectly with Swisschamp in pair, but I consider it too long for keychain. Also, I like using this knife in the kitchen (I never use kitchen knives) and do not like taking things from keychain before using. It is probably my most used knife.
Climber is good on keychain, but does not have all tools, so it is the second most used knife after Pickniker.
So, they really perform different tasks.
Wenger is also a good knife company, I would like to get myself Ranger, but until I have Picknicker I won't buy it just because of my principle never to have things I do not use - I have enough reserve of good knives, so cannot justify as for PSK (but this year I plan to travel to Kyrgyzstan and Picknicker will probably become someone's present there

and then I will get myself Ranger).
My wife loves her Wenger Basic for travels and Victorinox Classiс for keychain. I also like her Basic, I used it before, so it is about 8 years now. But I found Classic a waste of money for a man - 2 years ago I worked on an island in Persian Gulf. Since we did not know rules of travel to islands, I did not take any of my knives, except Classic. It was my only knife for 1 month and, while it was reliable, I found it too short for comfortable use and did not want to use for serious work.
It is difficult to say which one is my favorite, I like them all, except Classic. And my wife loves Classic because it is cute.
Regards,