Yosemite IOS - Wifi Problems Check In

I updated to Yosemite IOS on my iMac and daughters MacBookPro a couple of months ago (and subsequently the Yosemite Update about 1 month back as well).

Wifi immediately slowed down to a complete stop when trying to download webpages after the initial Yosemite Update. It happens most of the time, although sometimes it works ok, only to start slowing down again randomly.

Daughter says her MBP works fine at school and at her friends' houses. Everything was working fine for both of us prior to upgrade.

Router is new Asus RT-AC87R. Got it maybe in August and it ran GREAT with previous IOS for about 2 months prior to upgrading to Yosemite.

After MULTIPLE HOURS researching, AND a stop at the Apple Store (LOL=no help at all), I have determined it is related to WPA Security in the router. When I switch Security to WEP or Open, everybody's computer works perfectly.

Anyone have similar issues, and/or fixes for this? Waiting for next Update, but in the meantime having to run either WEP or use Ethernet Cable for connection.

ETA - There are about 1000 pages of discussions about it online with a quick search. None of the other "solutions" work for everyone, but I have found WEP works for some reason.