After attempting to use the CSS3 Pie method for achieving some CSS3 support in IE browsers I’ve unfortunately come to the conclusion that it is still far too buggy for any kind of use other than for testing or demonstrations.  It has a pretty significant issue with the way that IE8 and lower hand page zooming in that any background image that you have will remain at it’s fixed size and simply tile.  Here’s a screenshot showing what my tabbed quotes example looks like after zooming:

Here are a few other issues that I’ve run into as well:

1. Noticeable delay on style rendering when page first loads. When you first load a page using the CSS3 Pie fix there is a small delay before those CSS3 properties are put in place.  This delay increases with every element that has some type of CSS3 style applied to it.  So if you wanted to round the corners on 100 divs on a single page you could be seeing nearly a full half-second delay before those are rendered on the screen.  It appears to be affected purely by machine speed so even people with a very fast internet connection will experience a delay unless they’re on a powerful machine.
2. Many “position: relative” hacks required on more complex layouts. The more complex your styling gets the more you have to utilize the “position: relative” fix that is recommended on their site to trigger the proper layout method in IE.  This becomes extremely cumbersome as you go on with a layout as it isn’t necessarily used in the same elements every time, which leads to a lot of wasted time hunting down the particular element which needs the style applied to it.
3. Sometimes it just doesn’t work. Occasionally a page will load and the CSS3 Pie will not load at all this leaving it in the default styles.  This happens infrequently but the fact that it happens at all seals the deal on whether or not I would feel safe using this method for anything other than a proof of concept or demonstration site.

I’m sure the problems with CSS3 Pie are purely related to having to work around the huge amount of shortcomings within the IE browser and I applaud the author for getting it this far.  For now, though, I would still recommend against using this for any type of production work.