I want to note something that my interest some:
The second biggest fear which made Sun sue Microsoft was that when MS licensed Java, their VM was faster than Sun's. Microsoft is (was?) the king of JIT. Technically biggest since if theirs was faster, they wouldn't have cared for Microsoft's anyway. Even now CLR is generally considered much faster than JRE.
I don't know how Chakra compares against v8 but then it also depends on what makes money for MS.