First, I'll confess to being one of the world's biggest fans of the Triumph 10 sedan and wagon. That said, I'm also a realist. From what little data is available, I would guess that a stock 1952 Willys 4x4 pickup is worth roughly twice as much as a stock Triumph 10 sedan in equivalent condition, so I'm not recommending an even swap as such.
Beyond value, both have their place in today's world, with the Willys still being a very capable hauler and the Triumph being an enjoyable and economical around-town ride. Neither (in stock form) would be very practical on today's highways at speed, but that's generally not why people own either vehicle!
Parts are not terribly difficult to source for the Triumph, but some -- if available at all -- might have to come from England and one might have to dig deep to find them. I'd guess that parts support for the Willys is rather better.
Obviously it's an apples v. oranges situation. You don't see many of either vehicle, and both would draw attention wherever they were!