Good news! X1® Enterprise Client (formerly X1® Desktop Edition) is now FREE!
I used Yahoo!® Desktop Search (a clone of XDS) because XDS was not free. I talked about this last year. Since X1 is free, I have already switched to X1. 
New for X1 Enterprise Client 5.5:
- New Look & Feel
- Client/Server Federation Option
- Real-time Outlook Email Indexing
- Real-time File Indexing
- Drag & Drop
- General Performance Improvements
- Outlook Calendar Support
- Outlook Task Support
- Attachment Preview within Email
- Range Searching
Go and download it now at http://www.x1.com/download/.
