I prefer Avisynth myself, I guess I'm not used to Vapoursynth.
There's a consideration for Avisynth in that legacy support should be offloaded, and have Avisynth primarily 'clean'. Basically to use a plugin requiring legacy support, you call the plugin for legacy support plugin commands, like:
legacyplugin(dooflakey(str=2.5))
Ideally thought the legacy plugins should be updated, not Avisynth. It's coming up to 2017, really should only be using 64-bit anyway
. That would probably make things a lot easier if only the 64-bit side of things were developed, and have the corresponding plugins updated.