I only just have enough space usually to get the frame and wheel in the u-lock. Any shorter than the standard size and I have to leave the wheel out of the equation. I'd be fine with that if I really trusted the Nutfix to be more than just another delay/deterrence to thieves. I figure a double-locking Abus u-lock has to be cut twice with an angle grinder and that would create quite a scene in the places that I usually lock up.
My wife has a shorter Abus lock She throws caution to the wind and only locks it around the frame.