The Maids is a two-woman show that looks like a live performance. It was part of a series of films adapting stage shows to the big screen, so the intent is implant audiences in the front row of the theater. It's not flashy and it doesn't do anything to make itself any less "stage-y". If that type of movie doesn't appeal to you, then you'll probably tear your hair out after five minutes.
Many theater fans adore Glenda Jackson's style, but it is very distinctive, so if again, if you don't like it in the beginning, you won't like the rest of it. She and her costar, Susannah York, played their parts on stage, which explains their masterful timing and very rehearsed delivery. The story is pretty dark and convoluted: two maids hate their employer, so when she's out on the town, they take turns dressing up in her clothes and harassing the other. They also act out little revenge schemes which they can never fulfil in real life.
Personally, I found it much to play-ish and peculiar to be enjoyable. If you actually end up liking this one, you can try any number of live productions Glenda Jackson filmed or another dark, strange drama with Susannah York: The Killing of Sister George.