The Olympus E300 Evolt is too new to have much real world comparisons. Here is a side-by-side view of the specs:
http://www.dpreview.com/reviews/compare_post.asp?method=sidebyside&cameras=canon_eos300d%2Cnikon_d70%2Coly_e300&show=all
And here is a PREVIEW of the Evolt:
http://www.dpreview.com/articles/olympuse300/
Most people agree that the D70 offers more features than the Rebel.
Of course it also costs more.
Those same people say the Canon 20D offers more than the Nikon D70.
Of course it also costs more.
The Evolt could make things interesting.
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I'm thinking of buying a new camera. I currently use a Olympus C3040z. I was thinking of going to a digital SLR, either the nikon D70, Canon rebel, or the olympus evolve (I think that's the name). Has anyone used them against each other, or any other insights?

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