I've been to Loring Kitchen and Bar numerous times over the past couple of years, so I'm combining my reviews and spotlighting three notable visits that seem to cover a variety of occasions.
Nov 2012 - I phone LKB about a week ago to let them know we were planning a happy hour event for a friend's birthday and give them a heads up that the size of the group was growing rapidly at 25+. By phone, we had discussed a location such as the portico area where we could have a gathering space to mingle. When we arrived, they had instead opted for the very long booth/table (2 across). While it wasn't quite what we had expected, it worked out just fine and guests were able to move freely between tables to talk. For the size of the group, service was reasonable - very pleasant. LKB was able to bring out a slice of cake with a candle for the birthday as well. I had the Big Pink (served in a martini glass) and that was delicious. Groups of this size should expect a 20% gratuity to be added.
June 2012 - I had a friend visiting from Portland and we decided to meet at LKB for brunch before walking the Sculpture Garden at the Walker across the street. The bellinis were wonderful and the brunch meals were delicious. Service was good and we loved sitting outside in the beautiful weather.
July 2011 - A small group of my friends arranged my birthday dinner at LKB. After being seated, we were told that our friend from San Francisco who wasn't able to attend in person has requested a bottle of Veuve to be delivered to the table with his compliments. The presentation of the bottle was lovely and the service was wonderful. The dinner experience was perfect.
Generally speaking, decor and ambiance is great at LKB. The valet is complimentary which we all really appreciate. Service may not be spectacular, but I'd still rate it as good to very good. I think they are often just understaffed so you do need to be patient. Prices are very reasonable, especially brunch and happy hour. You can use Open Table to secure a reservation in advance as well.