WPA/WPA2 with my Nexus 7

I have this weird problem with my Nexus 7: When the WiFi network on the home router (AirTies) is set to WPA/WPA2 it is always stuck in the "login" phase and never actually connects to the network. The network icon shows that it continuously connects and disconnects. Now if I switch the network to WPA2 only, the Nexus 7 connects fine. But then, a Mac on the same network keeps forgetting the network and I have to insert the key by hand every time it boots. Switching back to WPA/WPA2 simply reverses the problem. I accept even suggestions to switch the ADSL/WiFi router, provided that you suggest one that you know works for both machines.