What is better is up to you but I recently picked up engineering and it's pretty fun. You can make your own ammo and scopes and there are a
number of useful toys. Having the ability to FD and break out jumper-cables can save a long corpse run if all of the healers are dead in a dungeon or raid. You get increased performance of pots through injector kits. And the tinkering enchants got buffed to be on par with regular ones on top of the added effect like a parachute and Nitro Boosts. Don't get me started on how much I love Nitro Boosts.
I'm a leather worker too. But most of the stuff worth making is BoE and can be purchased on the AH inexpensively. Leather also doesn't sell that well, especially compared to ore. Even leveling I was rather disappointed in the armor I could make myself. There are some nice pieces, but most of them took mats that were too hard to collect or too time consuming at the level I needed them for.
The short summary is don't think crafting professions are for making money, gathering is. Crafting is fun so pick the combo you think you'll enjoy the most. I hope my opinion helps you find what that will be for you.