Met helmets

I'm after some advice re helmets. Currently I'm using my MTB helmet when on my road bike and I'd rather buy another helmet that may be better suited. My local bike shop sells Met and Lazer helmets.

The Met Manta seems to be very aero but I suspect probably a bit too hot for local conditions to be using regularly. The other Met options are the Rivale and Strale but I can't really see any significant differences between them except maybe that the Rivale is slightly more aero.

The other option is something from the Lazer range.

It would be great to hear your thoughts.