I am using a Dahon C7 and looking forward for an upgrade to higher gear + faster speed.

I am eyeing on the Dahon Dash but heard some feedback that some parts of it is not tat good i.e. their gears in the latest models.

What alternative can i get? I prefer bigger wheel size (to cop with my big body) and can have better performance than my C7. My budget around RM 2-3K. Or should i upgrade to road bike instead?