>What's the deal with side-by-side vs. replace?
>
>I have only one object that currently uses msXML2, which i can easily recompile using msXML3. Is there any point to using side-by-side? or would you recommend (especially this much after msxml3 has been out) to just go replace and move on?

There are changes in how the parser interprets a few things mainly related to schema management, data typing and the XSLT parser. If you rely on any of those things that have changed you will need side by side operation.

Personally I've never run into any of those issues - most of the things that have changed are fairly minor, so usually you can just move on to the latest version.

I would go with replace mode and test everything to make sure...