Let's face it - the British do psychological suspense VERY well! This 1940 British production is more streamlined and suspenseful than the MGM version of 1944, as it sticks more closely to Patrick Hamilton's play. The MGM version had more 'back-story' and padding to it. I love Diana Wynyard - she was lovely to look at and seemed wonderfully edgy and vulnerable - I wasn't surprised to learn that she played the anguished mother in the West End production of THE BAD SEED - she's really only remembered today for this film and CAVALCADE (1933), but she's definitely worth watching. Anton Walbrook is a little hammier than Boyer was, and there are those obvious streaks in his hair to make him look a little older - but he has a wonderful moment at the films end when, quite suddenly, his eyes go wild and you can tell that he's completely lost his mind - might have been a nice touch if the 1944 had included such a moment. Highly recommended.
I've noticed that people seem surprised that MGM attempted to suppress the 1940 British version of GASLIGHT to avoid any competition with their version. I don't know why anyone should be surprised - Hollywood's business is a cut-throat one: remember that L.B. Mayer, along with Jack Warner and others, offered to buy CITIZEN KANE from RKO and then destroy it, all to appease William R. Hearst - fortunately they didn't (just imagine the history of film since 1941 if they had!) And although MGM didn't destroy all prints of GASLIGHT, they did manage to keep it out of sight for many years - I think I first saw it on a cable station in the early 1980s - I tuned in expecting Boyer and Bergman and got Walbrook and Wynyard - as it turned out I didn't mind at all, and have enjoyed it many times since! MGM did the same thing with Paramount's 1932 DR. JEKYLL AND MR. HYDE which, except for an occasional screening, went unseen (but much written about) until it came out on video around 1990 (under the MGM label - imagine that!)