Last I checked, none of them integrate with Maemo's included things (like the contacts app). Lack of integration prevents me from agreeing that they're "really quite nice". Instead, they come with their own contacts app, etc.

I wouldn't mind if the Maemo PIM was a separate package, even one you have to buy. What I do mind is: there isn't anything that transparently integrates with Maemo's existing infrastructure. Therefore, no such acceptable Maemo PIM suite exists.

The other glaring hole in the Maemo software ecosystem, to me, is the lack of an easy sync solution between Maemo data (contacts, bookmarks, etc.) and desktop data (Windows apps, Mac apps, Mozilla apps, etc.).

Like I said, I wouldn't mind if those were an add-on. I wouldn't mind if they were a for-sale package (from Nokia, or a third party). What I do mind is: they simply don't exist right now.