The problem is that both of them use different methods to track, and both depend on Javascript to interact with the server.
Neither is particularly accurate when compared to raw server stats.
I wouldn't worry so much about the specific numbers. What you want to happen is:
Increasing unique visitors over time, say month to month and year to year.
You want repeat visitors, and you want those numbers to at least remain a steady percentage of the unique visitors, but ideally, you'd like that percentage to rise too.
You also want to have an increasing percentage of unique visitors spending longer on your site.
Pay attention to the referrals, that is, how visitors are finding your site/page/content.
Search engines?
Links from elsewhere?
You want both solid numbers of incoming visitors from "organic" searches, but you also want incoming traffic because other people linked to your content. You want steadily even if slowly increasing numbers/percentages of unique visitors finding you because they clicked a link on someone else's site.