Indica is somewhat lower grade (still good, just not AS good) with a heavy high where sativa has a very mellow feel to the high (personal opinion)

Yes the effects are way different, smoking it is an instant feeling that goes up quick and lasts for 4-6 hours (depends on the weed really) but eating it takes up to 2 hours sometimes more to take effect, it comes on a bit slower but it does get to a much more intense high that lasts substantially longer, ive kept a buzz with no trouble for 2-3 days before when i ate some nice brownies