Work from external FW 800 drive?

[mikegs]

My one year old MBP is quickly running out of storage space primarily from images. My preference would be to store all image files on a external firewire 800 drive including working on the images through the Lightroom catalog. Has anyone every used an external firewire 800 drive as a working drive through Lightroom? Impressions? I understand the work will be slower than from the internal 7200 RMP drive but did you have any unforeseen issues?
Thanks

[Collin Bl]

Have been using FW 800 for back ups since Panther and even booting the Mac off the Ext HD while running Leopard < much larger HD footprint that Snow Leopard > was a little slower but nothing drastic, probably around 30 secs slower. Both main drive and Ext HD were 7200s