Amazing little box. The MXM-sized GTX1070 is clocked down just a tiny bit compared to regular "desktop" sized 1070s. The Skylake i5 doesn't feel like it bottlenecks anything.
You can drop 2xSODIMMs in there for RAM, a 2.5" drive, and an
M.2 device. I have a single M.2 SSD in it, but it's completely viable to use a smaller M.2 SSD as a boot drive and a spinning disk in the 2.5" slot for more storage.
There are videos and instructions out there showing how you can even replace the Skylake i5 "T" with an i7 "T", with the extra TDP not being impacting. Might be also possible to upgrade it to a Kaby Lake. This all voids your warranty though...
It gets just a bit warm to the touch after a long gaming session, and the laptop-sized fans are also a bit louder than your run of the mill desktop computer. But you'd normally have your speakers (or headphones on) that cover the extra noise, and this isn't a laptop that you'd get burnt on, so the extra heat isn't a huge issue.
It's a bit pricy for what it offers, specs-wise. You could build something with a mini-ITX mobo and proper GPU in a Fractal Design Node 202 for about ~80% of the (current) price, but that build would still be heavier, larger and less portable than this box. This thing is about as powerful, but in a 20x20x6cm form factor and ~2kg which makes it easy to take with you, including on flights in carry-on luggage.