Well I set my clients to 8.8.8.8 and 8.8.4.4 when I had them disabled, and I have no issue when I use the schools wifi.
I used both resolver with forwarder (setting) and just the forwarder.
Was upgrading from 2.2 to 2.2.1.
Resolver settings:
Default + I had enable DNSSEC, Forwarder, DHCP reg, Static DHCP.
I have been using pfsense at my school for that last 2 and half years with no issue (did change hardware from a netbook after the first year), I have always had all the settings setup to handle double NATing, and I so get a reserved IP (10.X.X.X) and it comes from just a jack in the wall.
Update:
I disabled DNSSEC (even though google supports it) and the seems to help though it might have been mostly pasubio since I re-enabled it and nothing has really changed. After a few days the problem has seem to have mostly gone away. Something will take a little bit longer to load or some elements will still go through the can't find, then found cycle. It almost like the DNS cache was wiped and then it had trouble re-populating it.