I have a simular problem. On the Mac I used fusion 1.0 - 3.0 now. I got rid of Fusion 2.x because of lots of little problems, high CPU, video glitches/slow unity performance etc. I installed Parallels 4 in May and it was hands down better than Fusion 2.x in so many ways. Cloning, Cloning to templates, Convert to templates, safe mode boot, 100X better sharing between host and guest, and just way faster.

That said I am heavily invested in VMware products that I support everyday at work, so I wanted to be on Fusion. So 3.0 comes out, I remove Parallels 4.0 reboot and install Fusion 3.0.

I try to convert my Parallels VM's....they go for about an hour and then tell me "Virtual Machine was not shut down properly" which is totally false. I created a new Windows 7 VM on Fusion 3.0 and I do like the improvements. The Unity mode is nicer, but not as fast as Parallels 4.0 The menu bar feature was great at first, but when I tried to add icons to the drop down, (active directory users and computers and other AD tools) I could not choose them, so I must drill down through that menu....which kills the joy for me.

So last night I removed Fusion 3.0 and installed Parallels 5.0. I tried to convert my brand new Windows 7 fusion 3.0 VM and the conversion worked just great. P5 is even faster than P4, which is faster than Fusion 3.0. Even more features now in P5 over Fusion.

IMHO Parallels 5.0 > Parallels 4.0 > Fusion 3.0.

Ahh another feature I like in Parallels.

By default in Parallels when you plug in a USB device it prompts you with, "Mac or Guest" and lets you make the choice. In Fusion it depends on if the Guest settings for USB. I have plugged stuff in, while a Fusion VM in Unity mode was on and wanted to use the USB device in OS X and wondered why I could not see it. Then I remembered that Fusion was holding it....after pulling it out and putting it back in and checking the USB device on another computer.

I can tell you what problem you had. USB device on both have always worked. In Fusion you need to go into the settings of the VM and and make sure USB devices are automatic or selected, before you plug the drive in. It should see it then, while in the Windows guest, and at that point you should be able to copy files to it. In Windows I would go into diskmanager to make sure the Windows Guest can see it. Is the external drive formatted with FAT32 or NTFS? If not it will only see it in Disk Manager and not in the file system (as a drive letter), if you have formatted it with OS X.