The problem with carrying with a round in the chamber is - you give up the opportunity to pull it, rack it, and say some really cool tough guy cliche which is a very important tactic
Seriously, though, it is entirely a personal decision one needs to make based on many things - does your weapon get taken off and laid down alot? How nervous does it make you? How good is your situational awareness and avoidance (more likely to have a little "heads up")? How good is your carry system? All of these are individual specific and the choice should be based on your individual circumstances.
I totally get the attraction to a manual saftey. A lot of it is from the idea of a preemptive command. Think "about.... Face!"; "click.... bang". Some folks have been working with preemptive commands for a long time and find they help their "rhythm".
All I would suggest is - anybody who prefers to carry with an empty chamber should practice drawing and firing from that condition while taking a moment to visualize possible scenarios. That is when i, personally, decided I didn't like it much.