My post here:https://bitcointalk.org/index.php?topic=448923.msg5667261#msg5667261
I think the best strategy for investing in Ethereum is a 50:50 split. Invest only half of whatever you were going to invest in the premine and use the other half to buy Eth when mining begins. No one knows but it's likely the price of ether will drop when miners begin selling their mined ether. This strategy also helps the X factor to be a more reasonable number for inflation rate in subsequent years.