The past 2 times I have visited Vegas, I have found my way back to Earl's.
The pro is that it is open 24 hours!! You gotta love places that accommodate the late night partiers, the gamblers, and the night owls!
You will find Earl's as you enter Planet Hollywood from the strip entrance. Be prepared for the line as it is ALWAYS busy, but the staff members keep the line moving efficiently so you'll get your sandwich in no time!
Sandwich prices are around $5ish - $8 ish so it is affordable if you have lost all of your money gambling :)
However, best sandwich I've ever had? Not quite...but I like that the sandwiches come out hot and it does the job for a quick bite to eat.
I'll probably find my way back here again the next time I'm in Vegas :)