I've been reading about MIPS and it sounds like it is worth it.
I have a shaved head and I fear these road helmets might not be the best for me.
Anyway I'm torn between the Giro Synthe (MIPS) and Kask Protone (no MIPs but I guess it is a good helmet).
Go with whichever fits better. The difference between a good fitting helmet and a bad one is more than MIPS will make. Also, if you're shaved then you already have that slip plane that MIPS adds ;)
MIPS does a lot to protect your head when it hits the ground. At the cost of ~30g I'd say it's worth it.
Normally I find a buff pulled up over my ears does enough to keep my head warm if I'm riding. Caveat: I do have very thick hair.