A rhetorical question as I am going to tell you what I found out today when I used them BOTH for the same shave.
I had a B&B member ask me what was the difference between the long comb and short comb Gillette heads was. Even though I own both I have never given it much thought as they are both very nice razors.
SO.... Today I shaved with a long and short comb New head razor at the same time. Both razors are Bob's Razor Works customs and both have similar handles (similar size and weight).
Blade: I was asked to use the Astra Superior Platinum blade. It is a nice blade so I was more than happy to break open two new SP blades for this shave off.
I used Shave Library Hemingway soap and my Trumper's branded Simpsons H6 brush and face lathered (yes you can face lather with a monster brush if it has plenty of backbone and the Harvard H6 has more than enough of everything to spare)
I shaved one side of my face with one razor and the other side of my face with the other razor keeping each side of my face exclusive to one type of New head.
I did my typical 4 pass uber close shave with clean up.
Both type of razor performed exceptionally well. Neither one misbehaved. No weepers, nicks, cuts, scratches, razor burn... also NO whiskers left at the end of the shave.
Both sides of my face are BBS and happy.
I suppose I am not the one to test things as I can get a perfect shave using a sharp rock it seems.
If a gun were held to my head I would have to say that the New Long Comb has a little more bite to it then the New Short Comb but the difference might not be measurable only perceived.
So there you have it. Another draw. Anyone considering either of these razors could just flip a coin to make the decision. They are both nice well made heads. Pick the one that looks the most attractive to you and enjoy it!