I thought it was above average for sure, but not as good as a proper season finale should be ( or is it the shows finale ??? No word as of yet ).
The ep was basically based around his sisters wedding. And sorry to spoil it if you havent seen it yet, but Chuck gets a new intercept put into his head (well he decided by himself to put it in his head this time). Also, this intercept is different and leaves us much to learn if the show does come back, I will be looking forward to news of whether or not Chuck is returning.
Overall have to give it a 10.