Do I get a better interest rate putting 15% down as opposed to 10%?

Not necessarily. There are two types of loans you could shoot for if you need to put down a percentage, these are: Conventional and FHA.Conventional loans are advantageous that if you make a 20 percent or more down payment for your home, you will not have to pay mortgage insurance to obtain your loan. You could also qualify for a Conventional Loan with only 5 percent down but you will have to pay the mortgage insurance premium for part of your term.An FHA loan -- no matter the amount of down payment -- requires an upfront premium and also a higher monthly premium. FHA loans are beneficial to people who do not have a large down payment saved up as it only requires 3.5 percent down.Depending on what your debt-to-income ratio's are, your mortgage broker can help you choose which option will be better for you in the long run.Feel free to check out my profile and give me a call if I can answer any further questions!Josh LundBranch Manager - Gold Star Mortgage

Possibly, there are other factors that determine interest rate also, primarily your FICO score.

Generally no, but you'll get cheaper mortgage insurance if you put 15% down.