The comments on this thread
have been going for almost 2 years now. The actual evidence which is linked to is the http://lotusnotessucks.4t.com/index.html
page which has been kicking around for ages, and uses examples from R4 to make it's points.
Reading the comments in the new guys blog, it's pretty clear that there are some people out there running some poor installations, and also that there are some people out there developing some unusable apps. Or worse still, some companies not doing any development at all - giving users the impression that the product is email only. Sure, it does email, but no one is going to argue with you if you say that the mail template isn't exactly the slickest interface out there these days. However find me another product which can run multiple websites easily, perform all my document management needs, perform all my invoicing, manage multiple knowledgebases, run a Helpdesk, and every other thing I do with Notes and/or Domino on a day to day basis - and then we can talk.
On another note (yeah thanks Ken!), check out his photos to get a supporting picture about the intelligent arguments he makes. Ugh.