Alec Guinness, an interesting story, and some effective dry humor make this a witty and satisfying satirical comedy. Like a number of the Ealing comedies, the initial plot premise is interesting, yet it is really only a pretext for presenting material that affords some opportunities for subtly caustic commentary. In this case, the far-fetched invention by Guinness's character is used cleverly to point out the ways that various persons feel about science, change, and technology.
Guinness plays an innocent, even naive, character here, which is rather different from most of those he played in other Ealing features. There is a good assortment of supporting characters this time, and some of the minor roles feature some effective performances. Cecil Parker, Michael Gough, and Ernest Thesiger make a good trio of heavies, and Joan Greenwood works well as a character in the middle of things.
The ironic, understated tone of most of the humor keeps things low-key but effective. It's the kind of approach that is far more challenging than direct ridicule, and it takes disciplined film-makers to make something like this work. Not least among the movie's strengths is Guinness's own skill in making his character believable in addition to sympathetic.
While in some ways the comparison may be a stretch, there are some rather interesting parallels between "The Man in the White Suit" and the much more recent "Jurassic Park". The style and characters are much different (though "Jurassic Park" is not entirely without its own moments of dry humor), but in both cases an amazing - and entirely fictional - invention is shown to provoke all kinds of differing reactions, as others seek to exploit it, to close it down, or to control it. In both cases, the point is not whether the invention is valid, but rather the ways that everyone responds while barely understanding or appreciating the actual development itself.
While "The Man in the White Suit" is not one of the best-known Ealing features, it is another good one, with wit, solid characters and story, and an approach that combines style and substance.