If you someday start using actual features of Module::Build that are not supported by MakeMaker, you can change it then.
I'd also suggest that until Module::Build is known to work on a lot of platforms (i.e. close to what the baseline perl supports) that authors supply an oldstyle Makefile.PL.
One module that I had been using for a long time, and wanted to upgrade for additional features/fixes, started requiring Module::Build in order to install it. Unfortunately at the time Module::Build wouldn't build/install on AIX 5.1 and its author was unfamiliar with AIX. Since AIX isn't well known this understandably took a while for him to debug/fix (of which I'm very greatful). Luckily the module I needed was pure perl so I could install it by hand in the meantime. If it wasn't I'd have to support an older version of the module indefinitely and eventually consider rewriting a fair amount of code to avoid using it down the road.