I tried it a few versions ago and went back to OE I need to be able to set a Proxy and port and it didn't look like I could do that with incrdimail Q. Am thinking of giving it a try again as I'm getting sick of OE. again. BTW, FireFox 1.5 is awesome... I just started using Tabs. Keeps all your windows open at the top with only one "tab" in your taskbar. Very nice feature after you start using it. http://www.mozilla.com/thunderbird/
I've been using the Firefox and Thunder bird for a while. Haven't experienced many problems. Only occasionally will I have to switch back to IE. I also have been using Mozelle's Sun bird (calendar software) with pretty good results.