(Shrug...) “Who knows? The past will always be with us...”

Makefile.PL started the ball rolling, and Builder sprang out of that and says that it's better. Whether or not it is, today we've got both. (And tomorrow, we'll also have “both.”) As an Implementor, evaluate both of them, and decide for yourself which one feels better to you today. Whatever you decide, it'll surely be a good decision for today. Over time, one-or-the-other will gradually fade out. (Maybe.) In the meantime, both of them will do the job. So, “no worries, mon.”

It's really a waste-of-time to ponder how the future will judge your decisions.

If you're doing something very simple (installing a pure-Perl module or set of modules without configuration), either one works fine. If you need to do something more complex, Module::Build may be easier to understand -- it's conceptually simpler, with fewer cross-platform moving parts.

I use Module::Build exclusively because I think ExtUtils::MakeMaker is a big ball of horrible hacks, and I want it to go away forever. Not everyone agrees.

Personally, I find the Build.PL method far simpler to parse in my head. So, that's the way I go. That said, I didn't find switching to be terribly onerous, so unless you have some really wacky stuff going on in your build, don't fret about it, you're not really locked in.