I think coin may turn table in crypto market, I found lots of information regarding their business ideas, team + how they allocate token via different media everything they have shown on https://www.icoguide.com/en/ico/stoxum

Is Stoxum token utility or share? Which opportunities does the buyer have?

You could call it share or equity token. it allows you to receive dividends

Yes, Stoxum holders have the several advantages:
- the right to vote for the addition of new tokens
- they can increase their income with multi-level partner plan
- earn trading commission
- use white label solution to create own exchange

Probably in tokens. because you do not have such a quantity of wallets to transfer your money accumulated in the Stoxum system to your external wallet

The users will acquire a personal purse for each cryptocurrency when they registered.

Dividends are distributed in the form of STOXUM tokens to wallets in near real time (once every 10 minutes). Before sending dividends, the system aggregates revenues in different currencies and purchases the tokens sold on the platform to be sent as dividends. This mechanism promotes the growth of the token itself, and also lets you keep tokens in your personal wallet, and there not attach yourself to a single exchange.

I see in description that STOXUM will use master nodes. What characteristics of the system should be for this?

I think this project is quite complete, the features and concepts that are offered so well, Speed, convenience, and security guarantee our transactions. I personally strongly support this project.