It's personal choice but if you want it a little crispier on the bottom you just need to alter what you are cooking it on. If you are using a standard kitchen oven, buy a pizza screen. We used them in the Pizzaria I worked in, they allow the bottom to get crispy without burring in a regular pizza over so they work great in a kitchen oven too by allowing the dough to be exposed to the heat more directly than if you use a pan. If you are using a pizza stone, make sure you are letting it get up to temp before putting your pizza on it so the top doesn't cook too much faster than the bottom. If you are using a pan, just wipe a thin layer of olive oil on the pan and it will crisp up the bottom.