Well worth trying
Stayed up most of the night installing and testing mail readers (after discovering that KDE's kmail occassionally loses mail, needed a replacement fast for several workstations). Of all the mail readers that were listed on Freshmeat, Arrow looks the most different - different enough to put me off on the first pass. But after trying a number of others that looked more like the standard model (a half-dozen at least look just like kmail!), and watching them fail to compile, crash, show immediate bugs (including trouble reading standard mail boxes for several), took a 2nd look at Arrow, and discovered it looks different because it's real engineering rather another knock-off of a tired old interface. After a half-hour learning curve, it's the most pleasant mail reader I've used in 17 years online.
One little problem - it loses mail
Version 1.0.28 anyway, installed on two different systems, would occassionally show blank email titles with no message attached. However, deleting these, in turns out, was deleting email that it was having trouble with, and the mail was lost. If you look at the kdm bug-tracking system you'll see that kmail has a number of unresolved bugs, which is understandable and even forgivable in a fairly young program - but losing mail should never be tolerated in something widely distributed as part of the kdm environment.
A long night testing all the email readers listed on Freshmeat produced one that looks truly promising, with a fresh design and inventive features: arrow. Others have interesting designs, but immediately apparent bugs, or use nonstandard mailboxes, or are just plain ugly. Kmail isn't so ugly on the face, and has fairly nice mail sorting (altho procmail is worth the hour to learn, and more powerful) - but nothing's uglier than losing mail!