This place is awesome, and the food is incredible. I've been to puh-lenty of pubs/restaurants (both the re-created domestic retail variety and the original overseas kind). Lis Doon has a great atmosphere and awesome music. There are people of all ages having a good time in the open area. People dance, clap, sing along. It's great.
Do not go there looking for a fine dining experience (duh). It's more bar/pub than restaurant. If you're easy going looking for a well-poured Guinness, this is the place. If you're picky and require Fancy Catsup, then please stay way so that you don't ruin it for the rest of us.
(One star less than perfect because a couple of the high-top pub tables are a bit uncomfortable--until drink number two.)