I don't think this is the right attitude to have. You should judge IE9 by its own merit, not by past misgivings. You can't (and shouldn't) be compelled to try IE9, but the reason you aren't using it should be that another browser works just fine for you, not because you wholeheartedly reject Microsoft for past suffering.
Also, it's my belief that the suffering we faced with IE is less an issue with the browsers themselves, and more of an issue with the update schedule. IE6 was very good at the time of it's release; it's a shame that it took so long for IE7 and IE8. But now, with Chrome (and now Firefox) releasing several major versions a year, we should see more and better developments in the browser space.
If for some reason Firefox, Chrome, and Opera didn't work out for me, only then would I try switching back to IE. It is the order in which I would try the different browsers that the history of IE is considered. I don't see myself considering a switch anytime soon since I love Firefox.
You should at least try it, even if you have no intention of switching. IE9 is blazingly fast on my netbook, even more so than my browser of choice, Chrome. While I have no intention of switching right now, it's a win for everyone that IE is a serious competitor - once IE9 has mainstream adoption it'll push Chrome, Opera and Firefox to be even faster to stay ahead.
Also, it's my belief that the suffering we faced with IE is less an issue with the browsers themselves, and more of an issue with the update schedule. IE6 was very good at the time of it's release; it's a shame that it took so long for IE7 and IE8. But now, with Chrome (and now Firefox) releasing several major versions a year, we should see more and better developments in the browser space.