State of D toolchain & architecture support?

[dv]

Hello, I am currently evaluating D2, and have questions.

Language-wise, D2 looks very interesting to me. I do have 
concerns about the toolchain and architecture support, however.

First of all, there is DMD, LDC, GDC. Of these three, LDC seems 
to be preferred. x86-64 support is apparently solid, at least I 
was able to make 64-bit builds with LDC. But what about ARM? If I 
understand this correctly, the real question is whether or not 
the druntime library supports the architecture properly. This 
does not seem to be the case with druntime and ARM. Threads like 
http://www.digitalmars.com/d/archives/digitalmars/D/druntime_140097.html 
do not sound promising.

I do not wish to spend time learning something with a shoddy 
base. If I am to port or create projects with the language, I 
need solid architecture and compiler support. Can some D users 
enlighten me about the current state? Platforms I wish to 
support: win32 and linux. Architectures: ARM (v5, v7), x86 (32 
and 64 bit), perhaps also SH4 and MIPS, though these two are not 
necessary right now.