When I first searched for Turing complete blockchains towards the end of 2015 Google returned both Eris and Ethereum at the top. My initial impression was that they are quite distinct. More recently though I read that Eris is a spinoff. What exactly is their relationship, if any, and how do they compare?
Disclosure I'm the CEO of Eris Industries
eris is a blockchain application platform which normalizes many development activities when building a blockchain backed application. It is agnostic as to what the underlying blockchain technology; although admittedly when using some blockchain clients
eris provides nominal value beyond configuring, starting and stopping (e.g., it doesn't currently allow you to, say, put an EVM over Zcash).
With respect to smart contract enabled chain clients
eris provides a range of tooling beyond simply configuring, starting and stopping chain clients.
We do make a blockchain client as well, called
eris:db. eris:db was the first to market with a permissionable blockchain design. It is a tendermint consensus engine connected to an application manager (which contains a permission layer) connected to a built to specification EVM.
eris exposes a lot more tooling around eris:db (via the
eris chains namespace) as permissionable chain clients have more complexity to properly work with.
We think that right now the EVM is the market leading smart contract interpreter and it is true that we have a range of tooling around the EVM.
I've answered more of the differences between geth and eris:db here.
Eris is a services company that targets banks to deploy private blockchains. They employ Ethereum and have forked it but also seem to include some other technology and wrappers that provide additional tools for private companies to leverage blockchains. You can see a lot of Eris' git-hub projects are related to ethereum.
Here is Preston Byrne (Eris Co-founder, COO) talking about their view on blockchain and how private companies can use it.
This slideshare might also help distinguish them