I switched recently to Konqueror and Kmail.
Kmail works just fine and i am happy with it.
There are, however, some minor issues with Konqueror.
Example one. Printing works sometimes, sometimes not. I was unable to print a coupon out for a free exam for a vet.
Also, if i go youtube, it doesn’t play the video. Plugins are there, so in theory it should work.
Right now, this is under KDE 4.4.4 and Konqueror same.
Haven’t checked if thats actually a common bug.
Otherwise works fine.