depends on how much you are willing to put in.

you will have to buy quite a significant amount of NEO to earn GAS
for example:
you can buy 500 NEO right now which costs you about $34.000 dollar
you would generate about 73 GAS every year
1 gas is about 21 dollar in today's market
which gives you a profit of roughly 1500 dollar annually.

that being said
I think for instance Vechain will give you more chance of a higher ROI down the line for a lower initial investment.
although I do not know the worth of the thor coin (equilivant of GAS) I predict the percentage to be somewhere in the same ballpark.

take a look for masternode coins also there are lists online if you do a little digging.

but please be aware there are a lot of scams out there promising u X returns.