Before I begin, I'd like to share what is perhaps the greatest quote on bulettes ever, found in the 5e Monster Manual:

"A bulette loves halfling meat the most, and is never happier than when chasing plump halflings across an open field."
That's right, imagine one of those things running after a few panicking halflings. Isn't it wonderful?

Bulettes themselves are just another big melee beasty with a few tricks. They've got Huge size, very good ability scores and full BAB hit dice going for them, as well as a couple of pretty neat natural weapons.

Related to this is their Leap ability, which allows them to replace their bite attack with two more claw attacks. Good to have, but made even more awesome by the specific wording only prohibiting bite attacks. A Mouthpick weapon, for one, can still be used together with the claws.

Taking this into account, the bulette is a potent melee combatant that brings some very big numbers to the table. +1 LA seems about right.