Before Oct 19, Java was a no-brainer as it included both. Not anymore I am afraid.
IMHO Java gives you tons more freedom but you need a bit of computer savvy to really make it shine. I play MC with Optifine and high res packs and it looks miles better than what Win10 edition delivers. That said if you got friends who play on mobile/xbox via Realms, you want Win10.
One aspect not touched on this thread yet is VR. Win10 solution is quite seamless and polished, you just get the free app at Oculus or Vive store and it hooks into you MC Win10. Java takes a bit extra configuring. You need to install ViveCraft and then you can launch it from SteamVR. Takes some manual tuning but you have a lot more freedom there in terms if controls. Minecraft in VR is one heck of an experience.