I think it's just two different weapons, you can replace the HB with a Multimelta, and add a tornado pattern multi-melta also.
I feel like Laser Cannons are just too expensive 20 pts gets you only one 1pt of strength and you lose the ammo flexibility of the ML.
Plus the Landspeeder meltas can take care of any heavy tanks.
Landspeeders are expensive (not to mention time consuming to build and paint) and I only have two right now, so this list will be a long time coming.
Thanks for the input