hiel, this is interesting. i rebuilt a box last night to pick up the latest versions of gcc and glibc. (i've been using the ones that are so famous for breaking people's systems.) i used tcupdate, and it seemed to take an awful long time to compile glibc, but now i understand that the reason for this is that under the tcupdate script, glibc gets built twice before building binutils and gcc.
even though glibc-2.3.4.20050125 and -r1 are supposed to have serious problems, i'm happy to say that i've never run into them. the toolkit rebuild went well, and that my system is now rebuilding world files with the newuse parameter without any problems. i would have sworn that the order of the build should have followed dirtyepic's suggestions, but i can't argue with the script's results.

so i'm still inclined to think that proper cflags and proper maintenance of the toolkit could be something that the majority of the people who are having problems may be missing.
on those other occasions where the tc rebuilds seemed to be taking much longer than expected, my observations were based on total time required to complete the script, not the total time for any step in the process, such as glibc being recompiled twice in a row. the observations were made on a slower box feeding code to a faster compiling assistant via distcc. the delays were probably attributable to processing overhead on the slower box with too many instances of gcc multitasking because of a high value of j. i think that the older pc just became overwhelmed with preprocessing, and the other boxes on the farm were in a wait state. in short, i've learned that even if you have a big distcc assistant farm, a slow box is still a slow box, and your performance under distcc is not determined by the bandwidth of your compiling assitstants.
thanks.