I purchased the HomeRun deal - $1 for admission AND a free cup of draft beer. DEFINITELY worth it! However, I doubt I'll come back on a night they charge cover (which is basically everyday, I believe).
It was my first time at a piano bar, and was pleasantly surprised at how fun the night was. My friends tell me that piano bars in San Diego play contemporary and top 40 songs, so I was expecting to jam to piano renditions to the latest tunes. Although I didn't know several songs the piano duos played, I still found the live entertainment fun and lively.
If you find a table, the waitresses are very attentive and come by often to check if you're thirsty. I don't know if they do this every night, but they have a contest for a free party at the Big Bang for 100 of your friends if you could name the "corniest song of the 80s" -- this was our topic of the night. People would write the name of a song down on a napkin, put down cash, and the pianists would play it and wait for other patrons to outbid you.