I've been using evolution for the last few years. It has a EWS (exchange web services) client that works really well for me at $BigCorp. I think I've had one or

I've been using evolution for the last few years. It has a EWS (exchange web services) client that works really well for me at $BigCorp. I think I've had one or two crashes total, compared to outlook which crashes almost daily. Prior to that I used gmail. When I used thunderbird it often seemed to spend all of it's time indexing. It has some nice plugins though.