An izakaya is a distinctly Japanese form of pub, where the focus is on groups of people gathering to drink, and finger food gets served on the side. You order the food by the plate, but the plate sizes can be large enough to serve 4 or 12 people (party platters), and it's often very greasy dishes to offset the alcohol. The most commonly consumed beverage is beer, but you can also expect sake, whiskeys and mixed drinks to be on the menu. The idea is to create a party atmosphere, which is why many companies will hold their year-end events (bonenkai) at izakayas. And that's when things get crazy.
There's no real maid izakaya per se. Little TGV is based on a train chaser theme (staff dressed up as station personnel, with the menu items named after stations on various train lines), and Little BSD has the staff dressing up as various anime or manga characters. I have reviewed Little TGV before, but I want to list Maid Izakaya separately because these places aren't exactly cafes. There's no dinner menu, and they do advertise themselves for hosting group parties. As can be seen from the name, they belong to the same umbrella company and are just across the street from each other.