Well, after a few hours work the first dedicated chair makers bench in Sumner county is complete. First and foremost I think any bench should be massive, heavy, thick, and won't dance across the shop in use. The Roubo style fits that bill perfectly. But beyond that a chair makers bench should be slightly wider (26 1/2'') to handle the rake and splay of the legs. Not too wide since carving a seat involves 180 degrees of movement around the seat while carving. That is why the top is shorter (4') in length. 
The leg vise is very powerful for holding seat blanks in place. I also made the chop 9'' wide for more purchase on the seat and also for the leg jig when drilling the undercarriage assembly. The vise is closer to the end of the bench for easy carving on end grain. The Benchcrafted vise works just as sweet as the video you see on their website.
I have four of the hold fasts ready for use around the bench. These are a must for holding the seats in place while carving. The top is 4'' thick and I drilled a 1 1/4''counterbore underneath every hold fast hole leaving only 2 3/4 thick material. I have had problems in the past with them not holding in thicker tops. This always solves the problem. Matthew O'Neill also gave me a good tip the other day of using a center punch on the shaft of the hold fast to help grip the hole. Good stuff.
The base has the same shelf like my other bench using ship lapped boards which float on cleats.
The biggest improvement was eliminating the tail vise getting all the dog holes out of the way of the chair legs. I also moved the hold fast holes closer toward center for the same reason. I like the split top design without a tool tray but open on each end to use clamps to hold chairs in place after legging up. The gap is 1 3/4'' wide to accommodate the style of clamps I use.
Overall there is not really a lot of difference other than just tweaking a few things that kinda bugged me about the other bench.There are things that will still work better on the other style bench so it's good to have both. Especially when I have four students at one time. You all let me know what you think. Happy chair making!