Laptop drops wifi when moving from one WAP to another one, with same SSID I have two WAPs in my house with the same SSID, different channels, far apart from each other to offer coverage.

When I physically move my laptop, while on, from one to the other it loses the wifi connection. I have to turn wifi off then back on to get it to work again.

I have other devices, iphone and Android, which manage to work seamlessly across the house. The only problem is with the Mac laptop. Also, it used to work. This might be just a problem since upgrading to Yosemite, but I'm not sure.
i have had this exact issue with 2 SSID's with the same name.  i believe airport uses some kind of UUID for each AP, and gets confused wehn it see 1 ssid with two different id's.  you can do it with cisco (etc) gear where the ap's are part of a managed network.  but i never got it to work well when there were 2 with the same name.

you could try deleting both from the known networks and try to clear out some of the old info.