All comes down to personal preference. I have convex gold leaf buttons in my cabs at the moment, as they have shorter activation travel and don't click. I believe they're popular with fighting gamers, too (don't play them, myself) as it's easier to quickly move your fingers across convex buttons, or something.
I associate concave with my childhood. Here in the UK anyway. I always thought the flats to be a bit bootleggy wrong in the arcades. Not that it mattered i'm sure.
Yeah, the old 'starpoint' buttons were often to be found in generic JAMMA cabs, running bootleg boards. They felt cheap and would often stick.
That said, spent yesterday drilling into plexi for my control panel. Now I can put my concaves in, they feel a bit, hollow clicky rubbishy to the press. Have I just forgotten what they felt like in the 80s or are there different levels of quality out there?
Probably more to do with the quality of the micro switches. Cheap ones tend to be very clicky, and take more pressure to activate. Also, a lot of cabs back then used leaf spring button, which kind of look like concave, micro switch buttons from the outside, but have a very different, click-less feel.