Flat front for me.
I have a big Haulmark trailer that I found on Craigslist.  The tongue on it is over 48" but I can't remember the exact length.  52" rings a bell.
I've used a V-nose trailer for non RV trips, and I honestly hate the V nose space in the front of the trailer.  I can't pack totes in a logical arrangement in the angular space.  I HATE IT.
I've heard of people with V-front trailer behind a class A or Class C, and they hated it.  Something about how the air flows around behind the coach, a V front trailer creates weird turbulence and affects how the trailer travels down the road.
I V-front works great for less wind resistance behind a regular truck, but it does nothing in that regard for a tall truck and camper (like I have) or towed behind a Class C or DP CLass A