typohoon missle launcher vs assault cannon

I am thinking about the dif between the assault cannon and the typohoon missle launcher for my speeders.

the assault cannon - 4 str 6 ap 4 with rending
the missle launcher - 2 str 8 krak ap 3 or 2 str 4 ap 6 blast.

I like the idea of the rending 4 shots or at least the chance to, I have always liked the assault cannon
but the missles offer the straight up str 8 2 hots which you do not have to rely on your rolls for rending with.

what is everyones pref?

I am planning on making the speeder with magnets to be able to swap out wps for what I need in any list.

I'd go with the missiles myself. relying on luck with the assault cannon seems like a big gamble, when the missiles give you everything your Hoping to get out of the cannon with no random factor.

The missile launcher has 2 big advantages over the assault cannon. It has twice the range, and it can be fired as a defensive weapon.

Well if ya want your speeders to be a fast moving tank hunter or monster killer go with the missiles. But if ya need a anti infantry unit go with the assault cannons. And If your going to field speeders go with three. Weather you go with the cannon or missile, 3 of a kind is devastating for your opponent. And if one falls you still got 2 more.

Range is my thing. Assault cannon rocks but its range stinks.

I like MM/HF. Cheap and usually gets the job done and then some. Next would be missiles. Other parts of your army should be able to deal with what the assault cannon would be shooting at.

so I am going with the typhoon missles and hvy bolter option I think, I was going to go with the hvy flamer, but if I shoot defensively with the missles it is blast templats and I will just try to force armor saves and this gives me a better option for ranged.
Also the model just does not look right when the gunner does not have a gun when it is equiped with the hvy flame and missles.
I may use magnets to be able to swap out the hvy bolter.