Thanks everyone for you perspective. Andrew's most of all. Yes, Wouter I was trying to make up my mind whether to keep it. I bought the lens primarily for video and the narrow depth of field and because the price was too good to pass up. As most of you probably know you only have one shutter speed in video and you need NDs to pre-select your f stop if it's too bright outside. I've decided to keep the lens and rent a 6.6" matte box when necessary as I already have a full set of 6.6" NDs.
The lens is sharp enough wide open and very sharp at 2.8.
Thanks again.