Personally, I really appreciate the 5074P, which from my understanding is about the same price as a 3939HP (or in the neighborhood of that price).
While I do like the flamboyance of the red-handed 5951P, I do find the dial layout to be extremely unconventional and the moonphase display to be almost a bit crude. The watch overall seems to have little Patek Philippe DNA (the dial is very unconventional, the case is about all that is recognizable as Patek Philippe). Overall, the 5951P is not a watch that I would personally be super-anxious to acquire. In all honesty, I love the 5004 much more.
But in the thin air of the super expensive watches such as the 5951 and the 3939H, I would acquire the 3939H or if I could substitute that with the 5074P (my favorite Patek Philippe watch period), I would.
Goodness I really love that 5074P. I need to take a trip back to Geneva just to see it again. Maybe I should save my money on the plane tickets and put the money towards my Patek Philippe 5074P fund. I'll stop rambling about the 5074P now. I've stopped (for the moment).