Web3js – Interacting with Coinbase and Accounts[0] in Web3.js

Every transaction requires a sender, a from account that pays for the gas. An invalid address error usually means that the sender hasn't been specified.

You can explicitly pass from for every transaction, like:

myCoin.mint(wallet, value, {from: web3.eth.coinbase})

Or specify it just once using web3.eth.defaultAccount = web3.eth.coinbase. The defaultAccount is then used whenever the from is not explicitly provided.

As pointed out by @Ismael in the comment and after some days spent working with both library I can confirm what he has written.

Truffle-contract is based on the stable version of web3 (v0.20), so it use promises and allow you to perform contract operation and methods in Javascript.

Web3 v1.0.0 (which is still in beta) use Promise and Promievents, so web3.eth.Contract allows you to interact with your contract like truffle-conctract but it has in my opinion more funcionalities.

One thing to note is that the utility of truffle test docs and docs gives you an istance of web3 and truffle-contract so (if I'm not wrong) you can't for now use web3.eth.Contract in .js truffle test.