Cool, ok thanks to both of you for the info. I am looking at getting one or the other, but was unsure. I have my standard 510 and love it for when I am out, it is small and simple, I have an ego 650 PT that I really enjoy at home. But the 510 dies so quick it would be nice to have the slender style with the longer battery life for while out and about.
Oh how about cartos? Can I use the same ones I currently have on a Mega?