What do you mean by "window roll-up"?

Also, the settings menu thing is weird - mine takes less than a second to load, and I'm on a machine with a 7 year old processor at this point. I almost worry that if that takes a long time KDE will be more miserable performance-wise, unless you've already tried it on here.

By the way, what distro and XFCE version are you running - just for good measure.

The outdated sentiment is probably based, honestly. I think it's gotten better, but there are rough edges. In the end, do what works for you.