I’m still printing my MPCNC, but I’m using eSun PLA+ (or PLA PRO, it goes by both names depending on where you buy it). I’ve done strength tests with it, and it easily has 3 times stronger layer adhesion than regular PLA. It also tends to bend like ABS, instead of shatter like normal PLA. The only down side to it is that support material doesn’t come off quite as easily, but since nothing on the MPCNC requires support it’s not really an issue.
It doesn’t warp or shrink like ABS.
PETG might be stronger, but it’s also way more flexible than PLA or ABS, and I wonder if that wouldn’t cause problems? Anyone know?