ClearCase is the reason why I will avoid all and any (and will encourage others to avoid) SW products by that famous three-letter company unless absolutely needed (but it never is)
ClearCase was as delightfully terrible before IBM bought it and before Rational bought it. Writing off all software from IBM because they sell some lame software just seems weird. It's a huge company. I'm sure some people who enjoy soup have written bad software but it's saner to evaluate whether software is actually good or bad rather than checking if the authors like soup.
Or maybe I should just send the PTSD bill to them