Hey Chelsea,

While I haven't plaid with MS in quite a few months, as my focus has not been on SEO lately, I have always found it to be fairly accurate. Although by no means immune to inaccuracies. They are just estimates at the end of the day. For something like what you are doing, I'd probably just use common sense and go with the most current models. It's possible that there are many more people out there with older models, hence the search volume. But common sense says that would be a dying market while 5, 6 users will be growing. That's who I'd focus on any way, assuming doing both isn't an economical option.