Mains powered tools are a god send if you are doing some heavy duty DIYing
(eg drilling into brick) but you can't beat a cordless for its "just pick
up and use" ability.

Even a cheap cordless will drill 30+ small holes* through 10mm sheets of
wood on a single charge. As for drilling into breeze block you don't need
hammer action for that as it's so soft

I think a 700W mains drill will be so heavy, it would actually be easier to
use a brace and bit just for chipboard. Cordless sounds a lot better.

john