The history of Zimbabwe, as seen from here via the media, is slightly strange. Mugabe and ZANU took over in 1980 and ruled, if not well, then at least averagely by African standards for twenty years. Then in 2000, came the land seizures, leading to the steady disintegration of agriculture, and eventually to the utter economic failure of today.
The assumption in these parts seems to be that Mugabe went bonkers in 2000. That is possible. But it seems at least as likely, based on the scant facts presented, that he held out against the destruction of white-owned agriculture for twenty years, and in 2000 could do so no longer. As I explained in the British context, it would be out of the question for him to defend his policy change in that way.
If my guess is correct, then the most important fact about Zimbabwe politics is that there is a powerful group of armed "war veterans" who will take what they want (land) and the most powerful individual in the country (Mugabe) is unable to stop them. If that is true, then the outlook, whoever is finally declared to have won the election, is not good.
It may be that the MDC, with western support, would be able to protect private property sufficiently for the economy to start to recover. If that is so, then the basic difference between ZANU and the MDC is that the MDC would have western support and ZANU doesn't. By a startling coincidence, that is exactly what Mugabe claims.
Aside from the destruction of the economy, the alleged evils of Mugabe are not so obvious. The level of political oppression that has been reported is what I would term mild to moderate: no worse than Russia and considerably better than China.
I suppose there's no direction to go but forwards, and forwards means getting rid of Mugabe and starting again with a new set of rulers who can accept outside help in restraining the "war veterans". But I expect civil war. My bet would be that Iraq will be peaceful and prosperous before Zimbabwe is.