Id say get both because there ARE time you don't want to be tied to a wire at your PC.
I have both and use them - when Im on the PC its the PT, and any other time its the manual battery.
Of course your next question will be what KIND of manual battery - and if you get something OTHER than a standard (like the 510 standard battery) then you'll get a better 'taste' because it puts out more voltage.
eGo
batteries (to continue with the 510 example) are better than standards, (at least for longer lasting and I think they give a better flavor too) and better than eGos are '
mods' like 'The Chuck' 'The BUZZ' 'prodigy' 'SB' 'GGTS' etc. Those can be from 3.7v ( a TRUE 3.7v) up to 6v.