TL;DR: I use Google Domains to buy/transfer domains recently for friends and small clients which only need a basic website, and I have very good experiences with Google Domains.
It has very clean UI, very simple and easy to use, straightforward, no hassle, no bullshit.
Flat rate at $12 for .com domain per year, with Private registry for free. ($20 for .me domain, and might have limited TLD or a bit higher rate comparing to others, but still cheap)
No COUPON whatsoever, just flat rate for every year.
(I'm laughing at GoDaddy which trick you get x% discount on the first year and get much higher rate next year. And you keep getting emails about expiring domains/and discount codes if you wait till the last day.)
No upsale. It offers partners site like wix.com, weebly.com, squarespace.com if you want to host website there. Or you can use Google App engine or any VPS to host website.
Another benefit is to easily integrate the Gmail for Business/Google Apps for Work.
So, now, why don't offer SSL certificates?
They have our Gmail, Google+, and they have very good ideas about who we are and can easily verify our identifies, to issue a Class-2 or wild char Certs. Don't they?