The SUN provides the standards for the JAVA programming
Language, SUN is where JAVA started, so still SUN knows what they are
dealing with!
Yeah jikes provides better error checking and so on and so on, but are
they standards? Providing non-standard extensions, makes the resultant
program unportable. You might know the case with C / C++, where after a
lot of quarrels regarding the extensions, we settled for ISO standards
for doing things.
So in my opinion SUN still provides the best compiler, and will remain
to do so ( at least it will be standard what others will follow )