My Knight D3 team has been carrying me. My last 6 seasons were: FF, E8, Title Game, 1st Rnd, Title Game, S16.
The odd thing is that when you get to the title game you get "Reward Points" instead of game credits. I've been using those Reward Points to support my GD habit, so I guess it works out, but it throws a monkey wrench in the calculation for me.
Overall with $290.75, I've played 30 HD seasons, have 5 in the bank plus sitting on $41 in credits. So without the Reward Points that went to GD (which is pretty significant), I'm running about $7.14 per season. Pretty good value in my mind.