Quote from the article:
“Canon EOS 300D is good by itself. At least by the fact that this is the first real reflex digital camera at the cost of a good compact digital camera. Its functionality practically didn’t suffer from the fight for the price. Interchangeable lenses, depth of field preview, manual and automatic shooting modes, RAW mode, external hot shoe, good image quality at variable ISO (100-800 settings). From its predecessor EOS 10D, the Rebel differs by its “soft” plastic case, controls, and smaller buffer size. But both hardware and software parts are mostly the same as in EOS 10D. This allowed Canon a “quick” launch of an inexpensive camera. This also allows to make almost 10D out of 300D (we should thank Canon for this opportunity, because it “didn’t break off the extra pins from the chips”). “
Check out the big disclaimer above the article before upgrading your camera.