I think my favourite field is weekend warriors and warpaint, i like how one can combine fields at both of those places, and the cost is very very reasonable.
I think my least favourite field is CTF nothing but bad experiances there, poor organization, false accusations by staff and other players that were complete unfounded and promtly proven wrong in seconds. I also find the fields to be very similar and undynamic. But its all down to opinions, if you like it all the power to you.