Since FUSE4X doesn't offer MacFUSE compatibility (code has to be recompiled against FUSE4X), I just went ahead and uninstalled MacFUSE and replaced it for OSXFUSE with MacFUSE compatibility layer, let's see how it behaves, but from my understanding Parallels only uses Fuse to mount NTFS volumes of VMs in Finder with read and write access, which is not something that I normally use as I don't like to see OSX's hidden files in Windows.
I personally hope Parallels goes ahead and replaces MacFUSE for OSXFUSE.
Another important issue is that MacFUSE's built-in uninstaller fails silently and doesn't actually uninstall MacFUSE, this happens on 10.6.8 and also probably in Lion, Parallels should take care of this.
OSXFUSE uninstalls MacFUSE if you select the compatibility mode (didn't test this as I already had MacFUSE removed by Tuxera's MacFUSE uninstaller).
EDIT: Strangely enough, without MacFUSE or OSXFUSE installed I can still mount NTFS Volumes from virtual disk in read and write mode. I wonder if FUSE is only used for mounting NTFS volumes of Bootcamp partitions?
EDIT2: Mounting Bootcamp disk on mac desktop works (by works I mean that not only does it mount but I can write to it) without macfuse installed, which makes me wonder why do we need to have MacFUSE in PDM. Unless for MacFUSE to stop working, besides uninstalling it (successfully) the computer also needs to be rebooted?
