[symphonix]

There is an agreement in place between Apple and Microsoft, as part of their court settlement, that goes something like:

- MS buys a sizeable chunk of non-voting stock in Apple (their incentive to stop attacking Applee head-on)
- MS agrees to continue producing Office for Mac for 5 years
- Apple agrees to make MS Internet Explorer the default browser for the Mac

So, Apple has agreed to put forward Internet Explorer as their browser for OS X, and I'm sure they would have trouble producing their own browser as they would not be able to include it as the default.
If there are instabilities in IE for mac, then the blame lies with Microsoft. The real question is whether they have deliberately allowed bugs to get through on IE for Mac, or if these are just the usual bugs you'd find in any project of this scale.
Now, in defence of MS, I quite like IE for Mac. It seems stable and fast most of the time and loads most pages with no hassles. I am suprised that it sometimes stumbles over pages that work fine under windows versions of IE, and annoyed that these crashes bring down the entire browser in a sudden crash.
It is not up to Apple to deal with this though, except by keeping the pressure on MS to up the quality, and to advise their customers that other browsers exist and some are of excellent quality.