I figured I'd finally weigh in.
I'd wager that I'm about a 5.
Like some others, I'm fully on board for FIRE, and expect to do so at the latest in my early 40s (33 now), but we're not necessarily frugal in all the right places which can tarnish the mustachian score. Rough numbers: $150-160k gross salary, $70ish-k/yr spending, ~40-50% savings rate, $500k liquid assets, $150k house equity, age 33, estimated FIRE, 40-45 depending on part-time work.
Pros:
* Wife and I both have pretty good base salaries (~190k total).
* We have no debt other than a mortgage, and we didn't overspend on a house according to the old 30% of your take-home rule.
* (both Pro and Con) We avoid daycare completely. My wife works 60% full-time, and I work 90% full-time, and my inlaws watch the kid 1 day a week. This leads to a pretty comfortable schedule that doesn't require daycare costs. However, the loss of income probably makes it close to a financial wash.
* We put away ~40-50% of our income into investments/savings each month.
* I spend a lot of time searching for an analyzing for the best cost/value when buying just about everything. I'd much rather buy something for a little more money that will last a LONG time.
* Neither of us has a spendthrift hobby or passion. Wife doesn't do the stereotypical clothing shopping craziness and I'm not a the stereotypical IT gadget fiend. Good for the wallet.
Cons:
* Food costs. Though we do not eat at fancy restaurants a lot, and know how to cook well, we spend a ton on groceries. ~$1000/mo for a family of 3. I like to eat a lot of good meat, and like to buy organic meat when I can. This is one area I've never even tried to reign in, but I'm going to attempt to in 2015 as a resolution.
* Overall cost of living. DC is expensive to live in, in general. I feel lucky that we're able to only spend $70k/yr as a family of 3, but sometimes I feel like a major slacker on the frugality front.
* 2 cars. Because of the distance of my commute and time commitments from a 4-day work week, I can't readily bike to work. I am REALLY considering getting an electric-assisted bike to do fair-weather commuting, but I wouldn't/couldn't do it in the winter. So... still 2 cars.