If you like waiting in line and being treated like an inconvenience, then Khao San Road is the place for you.
The food here is fine, but definitely not as good as when the original team worked here. More likely the lineup is due to the fact that it's a small-ish restaurant on Adelaide, which isn't exactly teeming with dining options.
Once you get in, you'll probably be seated at one of the communal high tops at the front of the restaurant. You will not have enough room to enjoy yourself. You will be banged into at least three times, more than likely by a member of the staff.
When you get your food you will be disappointed by the size. Yes, it will be reasonably tasty, but small. So make sure you invite a dieting friend and eat half of theirs.
Final tip: don't linger. Eat and get the hell out. The staff won't say this to you with words, but that's what the look they're giving you means.