Yahoo! Desktop Search review by PC Magazine
They liked it. It's quite a good review, they make some of the same points I made.
Lookout for Outlook + YDS covers what I need at work. At home I need to search Eudora. Looks like YDS doesn't do that, but X1 commercial does. So X1 + Lookout together would do the job. I'll have to see if X1 will offer an upgrade path at less than list price.