Double situation. Low buy-ins - a large number of participants, and it is quite difficult to get into ITM. High buy-ins - a lot higher level of the game. And not the fact that you will get to ITM (again). Me please the middle. )))))))
I prefer lower because is what I can afford and I know that if I lose it's all okay. But higher if is live or a big tournament, then it all depends in your mindset and stay calm to not end up losing everything too soon.
I would prefer as low as possible or even free but no venue really offers live main event tournaments which are under $150. The casino in my state here in Australia has 3 tournament series a year that have 3 main events that range from $1150 to $2300. Weekly satellites into these tournaments is what I'm going to play which start from $70. There's also the Aussie Millions sats that come up around october which I will play as well. Hopefully coronavirus disappears as soon as possible.
Personally I would prefer higher buy-in so there's a smaller pool of entrants. It's much more room for bad beats when you're adding thousands of entrants and have to play more hands to make it into the money.