yes works fine, I was on phpbb3 RC2 and the impex script was for phpbb RC5 if I remember correctly and all went fine. You will have a few tings not imported , avatars, passwords, permissions
for much infos, all went smoothly, Im legit vb members so with latest impex version that always better , make sure to have an impex 1.83 or greater if yu're not legit customer cos the tool is often updated and dunno if it's working fine with null versions, "sorry the gay english"