It is not okay to compare the two, directly. Talking about the code, NEM has a better code than Ethereum. NEM has a great API that can work wonders for a business. NEM's Blockchain is very secure and uses a trust based algorithm which allows the developers to choose from public or private Blockchains.
Talking about Ethereum, it is always a safe bet. ETH is the standard for smart contracts and all the token sales use the Ethereum platform with ERC-20 token standard. However, it is a little bit buggy at times.
In terms of market cap you should know that Ether is way ahead of NEM.