geoc, you just don't see the whole picture. yes, there is a gap of m/v weapons in those early lvl's, and yes, a magic weapon is a better choice than a vamping weapon during them (so you can defeat magic monsters)... but for you to claim that one p/s weapon is better than another during that range will cause people to use p/s over s/s shows that you are not yet experienced enough to offer sound advice to newer players (yes, you can provide your opinion... but please state it as that, not as something that "should" be done). even i do not claim to know what's "best"... i've got a lot of experience behind me, and have tested many things (with fighters... i haven't used mages)... but there are others more knowledgeable than i.
as i said earlier, i keep both p/s and s/s trained at least to my lvl, but if i were to pick one to train for a new char, it would be s/s. from what i've seen up to lvl 36, s/s has more lvl's where it is the better choice than p/s does, especially in the late 20's to mid 30's. and you've probably noticed that as you get to higher lvl's, it takes longer and longer to lvl. so i'd gladly take the (relatively) small disadvantage around lvl 15 to 20 in order to get the advantage in the higher lvl's. just my personal opinion though. someone of higher lvl's may be able to say whether s/s or p/s seems to be slightly higher in late 30's, 40's or higher.
--jason