Do you have to dig a pit?
Depends on the look you're going for. I like the ones that are covered. I think a stack of bricks looks kinda shitty, but there are way to do them nicely.
I'd recco to use fire bricks on the inside so your decorative bricks don't crack. Excessive heat can split stone and bricks not cured to withstand high temps.
I prefer them because adding a spit and doing a pig roast, or putting a grill rack on top of the pit is easy to do and gives you another cool option when entertaining.