FWIW the ARB is U shaped, and I believe so is the Warn and Smittybilt on the cheap side. As for the people worrying about it getting caught if you rig it properly it will stay in the groove. All you need to do is keep tension on it. If the line gets slack in it you need to check it before continuing to winch.
IIRC the more expensive ARB (lightweight) is U shaped and the less expensive is a bit more V shaped but still not too bad. I have a Tractor Supply block floating around the shop and I checked it and it is U shaped. A little V won't be horrible but you don't want a steep V like one made for smaller rope like on an ATV (1/4") and then smush truck line (3/8") into it.
This is the ARB I'm talking about I don't even think the wheel is metal but rather a polymer. I've used it with steel a few times and there were almost no marks at all. Thats with a couple of hard pulls too. Now I'm running synthetic and when I went to see how much I was going to have to polish I was surprised at the lack of marks on it.
I put some 3/8" Amsteel in a Warn snatch block today (rated for 3/8") and it looked pretty tight; it wasn't under any load though....
"The Devil's Highway Patrolman"
Enjoy that Warn 9.5XP it is a great winch, same model here and i really dig it.
06 UNL RUBI Locked /Armor
4.5" LIFT/35's /4.88
07 AT CHASER