My thought on sales figures is generally "who cares?", since what I buy is based on how well things suit me rather than what other people buy, but it's worth bearing in mind that phone maker's market share tends to be largest in their home country (very true in Apple's case BTW), and Huawei's home market is the most populous country on the planet.
As for Huawei, they make some solid phones, but their flagships perhaps lack a little of the polish of the traditional top brands (e.g. the bizzare decision to leave out an oleophobic coating on the P10). But they do make some very good devices.
I don't like think that blanket comparisons make sense, so "are Huawei better than Samsung?" or "is Kirin better than Snapdragon?" are the wrong questions to my mind: it only makes sense to compare specific devices and not entire brands, and then it depends on the needs of the user. And for SoCs it varies year by year: this year I'd rate the top Snapdragon (s835) above the Kirin 960, in a large part because the Kirin's gpu is too power-hungry. The previous year's top Kirin was more competitive, and it's too early to say how the next generation will compare. But you must beware of basing comparisons on specs, when it depends on your usage whether it will actually make any difference to you - and how the device works for you is all that matters really.