I have the zcp (vernis) and I love it! If you prefer smaller wallets go with the zcp, if larger than the zippy. I've found vernis to be relatively hard-wearing, but if I had my time over I'd go with the darker vernis colours, I have vert impression and I'm afraid of colour transfer... so it sits in it's dustbag in my bag, which is a pain. I wouldn't be so worried if I had got pomme or amarante etc.
it depends on how many cards you carry. i have 6 including my DL, so i put 1 in each of the slots in the ZCP and 1 behind in the back pockets. much more than that and you'd probably want the full size wallet.
I have the ZCP. I prefer it because it is much lighter, can hold 7 cards (3 on each slot on both sides and 1 in the middle), and enables me to accessorize with a cles for extra cards if I need them. The zipping to open/close is faster and simpler. I use my Sarah if I need a full-sized wallet, but I usually don't carry it as much. The ZCP is good enough for someone who has an uncomplicated life like mine.