I've had both the wired and wireless pik and the wireless one is my favorite even though the reservoir is smaller. I like that can take it into the shower and do my flossing there and it feels less messy somehow.
I have a wireless one as well (gifted) and it's good but find it's more of a hassle to use. Good for travel or if you don't have a much counter space. The one I got is battery powered so you have to change batteries and I don't have rechargeables so in practice I don't use it. I would probably use it more if it was usb chargeable.