Nowhere near as bad as drink driving, but still don't think it is a good idea. Too easy to drift off in thought and after all your driving a powerful vehicle. I'd probably drive too slow since I'm a slow driver anyway.
The government will just follow the money and power. There's a good argument for money now, although those benefiting from it being illegal will oppose it. But also public opinion is still split, and while split it can't win votes, so garners less interest from politicians.
It can work, but eventually gets found out so I have heard, but that's just what I have heard on the grapevine. I know someone who says he regularly sends single spliff in the post to thank friends with no trouble.a
A great reminder of how upside down the laws are on drugs:
Source: http://www.bbc.co.uk/blogs/thereporters/markeaston/2010/11/drugs_debate_hots_up.html
There was a great article on the BBC which compared all drugs and their effects based on a scientific study. Tobacco and Alcohol were among the worst, up there with heroin. Ecstasy and Marijuana was among the best.