I've been too busy to follow GCC development recently and haven't done any testing of development snapshots during the GCC 4.4 development phase so far. However, GCC 4.4 moved to stage 3 yesterday, the development stage dedicated to bug fixes and documentation. Given that GCC is now in stage 3 and that Debian unstable has fairly little churn because of the freeze, it's an ideal time to do some archive rebuilds.
I started archive rebuilds on amd64 and powerpc last night and added ia64 today. I also tried to build GCC on armel, alpha and sparc but there are compiler errors during bootstrap. mips builds fine but I haven't started any archive rebuilds.
I found and reported 9 compiler errors so far. Most of them have already received some attention and one of them has been fixed in the meantime. I'm not looking at build failures of packages at the moment since that's very time consuming and I'm not sure whether I'll find the time to report build failures later as GCC becomes more stable, but we'll see.