dunno about bug's and stuff, but you may well have to get some partitioning software (I use partition magic 8).
That way, it's reasonably straight forward to re-partition thing's.
I'd suspect that your main issue would be getting both linux OS's to boot.
When I previously had mulitple installs of linux distro's, I've usually had to make sure that I've got copies of the boot files backed up somewhere, then I've made a boot floppy for the first installed Linux distro.
After that, I've installed the second distro on the prepared partition(s) as normal, which usually overwrites the lilo (which is my prefered bootloader) files with the second distro's version.
Then I've had to modify my fstab so that the second distro can see the mount point's of the first. This was followed by booting the first distro with the floppy, and modifying the first distro's fstab so it can see the mount point's of the second.
Finally I've then had to copy the boot files back into the /boot so that when I modify the lilo.conf it know's which distro to boot when I select it.
I think that's right - it's been a while since I could be bothered to multiboot different distro's.
A slightly better way might be to re-partition so that you've just got your windows plus /boot, /swap, /root and /home.
that way, you can just install the SuSE over the top of the fedora in the /root partition and as long as you install all the same app's, they SHOULD run ok with the same customisations as any that you selected with fedora. If you then don't like the SuSE, you can just re-install the Fedora as you previously had it.
I think that you may also try the first method, but instead of having to mess around with modifying the fstab's, lilo.conf etc etc you could get a third party bootloader that will detect all installed distro's, and if that's the case you may want to repartition so you have the windows plus the /boot, /swap, /home and then have 2 /root partitions so you could run both distro's, but I'd think it'd be less stress than the first way I suggested.
Someone else might be able to tell you a better method
p.s. I've never experienced any bug's re booting window's with mandrake, SuSE, gentoo or debian/knoppix on hard drive - so I don't think that should be too much of an issue!