Even though it's rumoured that 5.8.0 will be released this Thursday, yesterday I took the plunge and installed 5.8.0 RC3 into /usr/local/lib on my iBook (Late 2001), running 10.1.5 and it passed 98% of all tests straight out of the box.
Make and test took forever (the iBook has 384 MB RAM) and 5.8.0 seems sluggish compared to 5.6.1 but with the very limited tests I've run, everything _seems_ to be O.K. If anybody else has been doing the same, I'd like to hear about their experiences :-) Regards, Phil.