My buddy has one of the original double bull blinds with the single large window in the front and the small port windows in the back. He got it about 5-6 years ago. I've used it several times. I just got the Double Bull double wide blind this past fall. Similar setup as his blind except the double wide door on mine versus zipper door on his.
The two differences are as follows:
1) Engaging the hubs on his versus mine are easier, so set-up is easier and quieter.
2) The fabric on his is softer, so getting in and out is quieter. I used mine in December MI hunts when it was below freezing and the double wide door sounded like loud crumpling papaer. Also, if you bump the blind from inside, it's louder on the new version.
3) Shooting my 60" Bear Super K out of my blind I have to cant it a little more than out of his blind. My 56" Super Shrew I don't have any problems with.
If I were buying again, I would try to find the older style recurve blind instead of the new double wide door new version.