Well, there's a lot of template stuff that can slow down the compilation.
You should use the "/MP" option and a compiler that support it (VS2010 probably, not sure for 2008). What it does is enable multiprocessor compilation, which usually speed things a lot (well, if you have multiple cores, which is very likely). I also think that the last versions of VS are a bit faster at compiling templates - you should try, VS2010 normally works on XP and VS2013 is available on Windows 7.
Also, templating can increase the size of the binaries - because it has to compile different template instantiations. I still think that 1 Mb for that is a lot, I will see if I can reduce a bit the exe size (when I find time).
That said, for a small project the difference can be noticeable, but once you compile a big project SPARK does not make a huge compilation time difference.
@granyte: can you post how you succeeded to configure CMake for proper 64bit compilation ? Thanks !