there was the same question the other day. if you want to use it on site, best get 110v. if its domestic only, go for 230v. maybe in future get one of each, but for now, a 110v may be best. just awkward having to carry transformer into house (and i can guarantee your going to use the extension on the 230V side!)thats a good point... but then do i go 110v or 230v...