You mean fundamentally? That would probably fill an own post. I think it is a question of believe (blocksize). What I found interesting though is that Microsoft research is not convinced of on-chain scalability (which would be block size increase). Here is a good article:
http://bitcoinist.com/farewell-bitcoin-cash-microsoft-chain-scaling-degrades-decentralization/

All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.