To me, it is anything but that.
Over the last few years I have used Outlook, The Bat, Eudora, different versions of Mozilla e-mail, and a raft of Linux mail clients in search of the e-mail prog that fitted my needs best.
Opera 7.5 beats the others on all the points that I need. Although it has a bit of a learning curve if you are accustomed to one of the others, its speed and flexibility are far better in the long run.
We all have our own preferences and needs, but for those with huge amounts of e-mail to search through, Opera has a real edge.