I've been happily using Mint MATE for about 4 years. The last Mint 17 upgrade 'Rosa' (17.3) was having some issues on my laptop, though. The display would lock up once in a while, a condition I could clear by switching to another virtual desktop and back (CTRL-ALT-F1, ALT-F8). But it was still a nuisance. Another little thing that was going wrong is this release didn't seem able to support an external HDMI-connected display (worked fine on the same hardware with Windows 8.1).
I heard that Ubuntu 16 was supporting MATE so I decided to give that a try. I've been running Ubuntu MATE 16.04 for about a month now.
The bumblebee packages are available from the Ubuntu repos, but as far as I can tell the distro just uses the nVidia device for everything by default. I found that I didn't care that much about the energy savings as I rarely run on the battery for more than an hour or so, so I wound up just leaving it this way. There is a setting in NVIDIA X Server Settings (PRIME Profiles) that allows switching GPUs on a global basis that seems adequate for controlling power consumption if I needed to.
Overall I'm pretty happy with this distro, but at some point I'll probably give Mint 18 MATE a try, also.
See: Linux Mint MATE 18 Or Ubuntu MATE 16.04