There are good ones for sure.  But the main caveat centers on the fact that the Japanese car industry is relatively young.  First, there are so few surviving vintage cars that date back in the 30s and 40s. If you can find one, they definitely are worth it if properly restored.  And then when you get to the 50s and 60s, the cars are quite unreliable, they are essentially poorly built and have little or no parts that have survived to these days for any respectable restoration work.

So what you are left with are Japanese cars of the 70s onwards.  That’s about the time they’ve started to produce quality efficient compacts but except for a few cars, mostly built by Honda, Nissan and Mitsubishi, there are few original parts to have them restored.  You might not be able to command vintage prices for these.