A must-go even if just once
I am from Europe but live in Shanghai. I think Malone's has a great reputation for several reasons. And I have to say, overall I like it so I go there about 3 times a month in average.
It's well located, it's cosy, there is outdoor space, the staff is friendly, the food comes in big portion (it's overall nice but do not expect anything fancy; a lot of the dishes are a bit gross, there to fill you up rather than giving you a dining experience). It's a bar after all, with good atmosphere and the drinks list is long... The margarita is not great, but I've still yet to find a place in Shanghai that does it just right, so no bad point there, really.
What I actually like at Malone's is the live band, called Art 6, part of the top-3 best music bands in Shanghai! They were invited to play at the Ceremony of the Paraolympics last Autumn so you can imagine they must be pretty good and friendly. They are good artists and those singers really make you feel like singing and dancing.
Anyone coming to Shanghai should visit that place in the evening, even if only once. This is a must-experience in SH.