It's easiest for me to answer this question in terms of what is WiX missing that InstallShield has ( feature gap ).
Bootstrapper/Chainer - WiX has a bootstrapper called Burn which is now included in WiX v3.6.
- XML Read - WiX only has CA's for
writing not reading ( AppSearch ) XML
files
- Text Search / Replace - InstallShield
has patterns for reading/writing non
INI/XML files
- MSSQL Only - No support for Oracle
and MySQL
- Automation Interface - No DOM for
programatically updating/generating
projects. Have to do it all with raw
XML.
No Native IIS 7 support - Native IIS7 support is present from WiX v3.5
- Mostly Text Only toolset. No GUI
Designers for heavy lifting ( see
IsWiX ). XML is concise and has it's
place but it's like comparing Notepad
to Blend.
I've used heat to extract COM fairly successfully so that's no longer a concern to me.