I use 10.3 on a G3/400 Lombard Powerbook with 128 + 256MB RAM and it's slooooow. Certainly usable but browsing is a pain when there is flash and/or (big) animgifs on the page. When just using the OS when not doing any other stuff I have to be patient, sometimes there's 'GUI-lag' running upto several seconds. The puny video hardware probably also doesn't help.
You could ofcourse always use OS9. Then again sticking a spork in your eyes hurts less, more likely.
