Pier 39 is one of those places that you think you have to go to when you're in San Francisco but is really just a hokey tourist attraction that probably doesn't really enhance a trip to the city. I guess that depends on your individual view-point and the kind of traveller you are though.
I am sure that families and especially the young ones would enjoy it there. There are rides and souvenir shops and lots of brightly coloured shops. There's a '7D' cinema experience, a carousel that was painted in Italy, and a mirror maze to name just a few of the attractions that will entice children.
There was a lefty store there which I did like because it reminded me of the Leftorium that Ned Flanders opens in The Simpsons, and also because I am left-handed so I appreciated all of the specialty items that most right-handed people wouldn't understand the significance of like notepads with the spiral binding on the right-hand side. They also had lots of merchandise embelished with 'I may be left-handed but I'm always right' which is a mantra I can get behind.
As you wander around the area the smell of lollies and other delicious foods waft about you, which are better scents than some of the smells that waft around you elsewhere in the city.
There are a lot of different dining places to choose from too whether you feel like Italian, typical American fair or anything else but what they are really known for is the chowder that is served in a hollowed out bread roll.
Among the shops you'll find there are: the NFL/College store which had the largest selection of baseball caps I've ever seen in my life.There are also lots of souvenir shops selling t-shirts, jackets, hats, key rings, bags etc adorned with various San Francisco related emblems (most commonly the Golden Gate Bridge), Krazy Kaps, Hard Rock Cafe Gift Shop, Fudge House, Candy Baron, and a lot more.
It's quite festive down there too with the big Christmas tree at this time of year. There are also great views of San Francisco if you turn and look back up towards the city and see the range of architecture on display from the Financial District and around to the North Beach kind of area, or of Alcatraz if you gaze out to sea instead.
I wouldn't say that it's a must-see while you're in San Francisco because it really is the kind of attraction I find it hard to feel is all that unique and I personally didn't particularly enjoy it there, but if you have children I'd say it's worth a visit and if you like to have the typical tourist experiences it's probably one you wouldn't want to miss.