Mixed bag. I think it's great as a secondary, tertiary, or specialized system, but wouldn't use it as primary.
The butterfly keyboard... I use mechanical keyboards with my iMac at home and massively prefer them, but the butterfly keyboard - despite being almost the complete opposite of what most mechanical keyboards stand for - gets the job done. I can type quickly on it.
Someone above said that the battery life, screen, and speakers are amazing. I completely agree. I still occasionally peer up close at the screen, just admiring how crisp everything looks. This is probably the only laptop I've ever used where I don't feel compelled to charge it every single time I bring it home. The battery life is really impressive.
The size and form factor still amaze me. It's so light, I carry it alongside an iPad sometimes and barely notice that I'm carrying something extra. It's so easy to take onto your lap and then set down somewhere else. It makes my 2011 MacBook Pro feel incredibly heavy and look dated, which is surprising because I can still remember when the MacBook Pro in those days represented a light and sleek-looking option compared to other laptops of the time. It's really a beautiful piece of hardware, although I'd guess there will be a day that we look back at the MacBook and feel that it looks dated, too.
The form factor is one potential downside, though. Specifically, the ports. I have almost every single port in my iMac occupied (and when I used my MacBook Pro as primary, all ports were filled, including the Firewire). It's partly for that reason that the MacBook could never be a primary system for me. One single USB-C port is far too limiting. The lack of peripheral access options is still a limitation for me, at times (going into work environments with flakey wifi, an ethernet port would be useful - but buying a dongle gets away from the principle of traveling light).
Another downside I've found is with the wifi reliability. I've seen other reports of it and it doesn't seem that we've discovered the pattern yet. Basically, after a few minutes - seemingly random, anywhere from five minutes to an hour - the MacBook will show that it's connected to wifi, but no net connectivity works. You're forced to turn off wifi and then re-enable it. I don't have this issue at home, with my AirPort Extreme-based wireless network, but have encountered it regularly with the corporate wifi networks in my work environments (as have other co-workers with MacBooks, but not other Mac models). For a computer that relies so heavily on wireless connectivity, that pickiness about wireless networks is a bit unsettling.
I use the 2015 model. Performance-wise the system is decent, but it feels like using a computer from a few years ago. Programs take a few more seconds to load than I've grown accustomed to with the near-instant opening of my iMac, as do websites. The 2016 model features a boosted SSD module that has significantly faster speeds, and I wonder if some of my complaints would be alleviated there.
Basically, it's a beautiful system that is perfect for a number of niches. I use it as a "work" computer primarily and a travel computer second, and for those purposes - none of which are particularly demanding - it works very nicely. However, if I were trying to use it every single day, doing all of my computing tasks on it, I'm fairly certain that I would grow frustrated very quickly.
As a buying decision, if you're in the market for a laptop, the MacBook Pro would probably serve you better as a primary computer. If you're just looking to have a mobile Mac and do most of your computing (and particularly your "heavy lifting" computing) on a different, faster Mac, then the MacBook represents a very good companion computer.
