Few years back I decided to go back to the original concept and do turnips for my Jack O'Lanterns, and what can I say, I love the little guys.
They also fit on my windowsill a lot better back when I was in a small apartment without a proper front step/porch to put them.
After sitting outside for a few days getting a little bit shriveled I think they look even better. This pic is actually from almost a week ago when they were freshly -carved, if I remember I'll snap a new pic of them later on
But yeah, I think they just generally have a lot more character than pumpkins, and you can usually get a couple turnips for the price of one decent carving pumpkin
The trick or treaters in my neighborhood always seem to appreciate them too, even if half of them don't seem to know what a turnip is (a disappointing amount both of kids and parents call them onions)