I'm not saying it was perfect, but it was far better than Outlook. And I have never once had to purchase recovery utils for Thunderbird, but to fix the fragile pst Outlook uses. I cant even count the number of times I had to do recovery for someone because IT was busy. Thunderbird never failed. At one point I just outright installed Thunderbird, changed the icon to Outlook and no one complained. I think I told them it was just the new interface.

Plus Outlook was a security nightmare anyways.