I have to disagree with Whistlingdeath. Tamiya is a good company, but it makes mistakes of accuracy just like anybody else. Take a look at its 1/700 Yorktown. It was promoted as a "new" kit two or three years ago. In fact the molds are about 35 years old, and the entire model is too small for the scale, its proportions are off, and the level of detail doesn't come close to current standards. Several of Revell's 1/700 kits are demonstrably better in just about every respect.
Then there are the Tamiya 1/350 battleships. The Yamato is a genuinely new kit (i.e., just a couple of years old). The Bismarck, King George V, Prince of Wales, Missouri, and New Jersey are 35-year-old kits, recently reissued in glitzy boxes - at much higher prices. Anybody who compares the Tamiya and Revell 1/350 Bismarcks will tell you the Revell Germany one fits together better, is much better detailed, is more accurate - and costs a heck of a lot less.
I'm no armor builder, but it's widely known that some kits from companies like Dragon, Tasca, and Zvezda have the edge on their Tamiya counterparts. It's also worth noting that Tamiya markets quite a number of kits that are made by Italeri - and some Italeri kits have appeared in Revell boxes.
As for aircraft, I haven't bought any of the Tamiya 1/32 kits (can't afford them), but I can testify that Eduard has quite a few 1/48 kits that are at least as good as their Tamiya counterparts - and quite a bit cheaper. And Academy's 1/72 P-51B can stand comparison with any 1/72 Tamiya kit.
Another comparison that's worth noting: the Tamiya 1/32 F-14 (which was originally issued about 30 years ago, but is still on the market - with no outward indication of its age) vs. the 1/48 Monogram one (which dates from around the same time). The big Tamiya one has flat instrument and console panels; all the details are in the form of 2-dimensional decals. The smaller Monogram one has genuine, 3-d instrument panels.
It may be true that "nothing on this planet is priced solely because the maker believes their stuff is worth more than someone worse." But plenty of manufacturers are able to get away with charging higher prices because their advertising convinces consumers that there's something extra special about their brand names. Anybody who's into photography knows that the great German company Leica has been trading on that phenomenon for many years. (On the other hand, I don't think Leica has ever stuck a 35-rear old camera in a new box, doubled the price, and told the public the camera is a "new release.") In my book, Tamiya is in the same category: good products at the time of their introduction, but not without serious competition. And I'm sorry, but in the cosmos of scale modeling you DON'T always get what you pay for.