If you snort it, it will start to affect you considerably quicker but it will also not last as long.
Some people consider snorting Ritalin (methylphenidate) to be close to the effects of snorting cocaine, including mood lift, talkativeness, euphoria, motivation, etc. These effects are similar to other powerful stimulants including amphetamine, which is why methylphenidate is used in the treatment of ADD and ADHD.
If you want to have the effects last as long as possible, the best (and safest) way to do it is to snort half of your intended dosage, and orally consume the other half.
If you have a full stomach, orally administered effects will take a bit longer to kick in, if you take the pill/tablet on an empty stomach, it will not take as long for the effects to kick in, but it will still take longer than snorting the pills does.