I will buy only BitUSD at a low rate 1-50 cents, I know that it will be pegged against USD, but BTSX has just started and it's value is going to up, so it is a initial risk. When we starting we pegging more than one currency then is a great opportunity for day trading, arbing. Like alt pointed out we have the risk of something going wrong and your bitasset investment disappearing.
I believe BitUSD / BitEur / BitGBP etc should start pegged to their value, all tracking the current exchange rates, then we can do the predictions on future value.