A:Answeri7 is faster than i5, however, unless you do a lot video editing or other task need super CPU power, i5 will be more than enough to handle every day job you through on it.
A:AnswerYes from apple includes a warranty I am not sure exactly what the terms are. Personally I am currently researching my options between Best Buy total coverage and apple care because the closest apple store is 3 hours away. I believe the warranty lasts 60 days. I honestly am not sure what is included in the warranty.
Thankfully Best Buy is a certified and approved by apple; and uses apple parts instead of generic ones in the event anything needs to be replaced,