try also IRC / bitcoin-otc.com - can check the trust score of sellers talk to people, might be a good idea to buy 10 x 100 btc from different people lower risk + more good impressions : )
Lower risk of losing all, higher of losing some
hm, if i'd be new, i'd for sure split my order at least among 3 transactions i mean all eggs in one basket sounds worse than for i<10 buy 100 btc ...