Hi OK,
1) PostScript fonts declarations are not anymore working. For instance this
\starttext \usetypescript[palatino]
You need to specify the desired encoding on this line: \usetypescript[palatino][ec]
2) Generating a format with XeTeX, that is creating XeConTeXt, is now possible but still MetaPost code is ignored in the resulting PDF file.
This is a problem in the XeTeX engine. It always uses the ^^-quoted form on every byte value below decimal 32, which basically makes it impossible to create a valid input file for metapost: There are no line endings written to in the generated file, but instead there are three-byte sequences, like ^^J or ^^M. This is why the new linux executable has the -8bit switch. That may be needed (or even working already) in the OsX version as well.
3) Even though typesetting a file with ConTeXt from within TeXShop works fine, still there is the warning
warning : use 'texmfstart texexec' instead
which means that some day those (like me...) who have not well understood how to switch to texmfstart (and in particular how to make it work...) are going to have big problems with the next releases of ConTeXt...
The (perl) compatibility scripts will stay around for fairly long time to come, so there is no reason to panic yet. ;-) Cheers, taco