What blockchain to choose for a project?

[semaforo]

    I'm working with a group on establishing a social investment platform, and we're going back and forth as to what blockchain to use.

   The colored coin implementation on bitcoin seems good, but then we are concerned about fees.

 The project requires contracts and easy analysis of embedded metadata on the blockchain. It also required contracts to be recorded on the blockchain.

  Ethereum is a little too centralized, and there are concerns about scaling/bloated or clogged blockchain hindering smooth flow. Also, the lack of a cap on gas means the network will likely only become more centralized with time, particularly with the shift to proof of stake.

  Ethereum classic sounds interesting but I have heard criticisms of the community- that there are not many active developers, that most of the people using it are just trying to get rich.

   We are concerned if we try to tailor our own blockchain it will be vulnerable to 51% or spam attacks.

     Can anyone make any recommendations?