Hello guys, I's not sure whether this is a correct thread to ask this.

Between mirrorless and DSLR, which one is the best in term of :

1)Ergonomic (Big body is tougher?)
2)Picture quality( Will focal length affects picture quality?)
3)Long term usage (future proof or not?)
4)Ability to fit several occassions (weddings,jungle,etc)

I've read several blogs but I'm still clueless on which camera should I get. Used to own a DSLR but not mirrorless.