I was a longtime Eudora user. Eudora has plenty of filtering capability, so I wouldn't choose Outlook for that reason. Outlook has filters, but they have not always been reliable for me, and I have never been able to figure out why.
I have not had corruption issues in Outlook lately, but had one some years back.
I'd be surprised if there isn't a way to export and import the address book, such as what is described
here.
I generally like Eudora better, except for one little thing - Outlook closes the open window when you press escape, and Eudora doesn't/didn't when I used it. On the basis of that single feature, I use Outlook.
Nice to know that my decisions are based on weighty analysis, huh?