Hi @Jeff welcome to the community.
OpenZeppelin 2.3.0 RC3 uses 0.5.7. See the forum post for the reasoning:
truffle-config.js specifies 0.5.7.
https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0-rc.3/truffle-config.js
const solcStable = {
version: '0.5.7',
};
Whilst the contracts themselves specify 0.5.0 and above.
https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.3.0-rc.3/contracts/examples/SimpleToken.sol
pragma solidity ^0.5.0;
I personally tend to use the latest solc version supported by my toolset. Primarily to include any solc bug fixes.
The solc release notes can be found here:
When you have a moment it would be awesome if you could introduce yourself and/or let us know what you are working on.