I'm new to Tezos. I have one question. Why would someone have a node in their computer? Keeping the PC on and using many gigabytes of storage seems odd. If people delegate to other bakers, then only bakers (which are not many, perhaps), will have nodes. So the concentration of nodes is likely to be high. Is this a risk for the network?
You will get "Full Rewards" if you run a node/baker by your own. If you use a delegation-service you will have to pay a fee (5 - 50% of the Baking-Rewards; depending on the Delegation-Service Service Terms).
You keep your Voting right, if you bake by your own. The delegation-service also gets your Voting-Right by Tezoss Design at the moment (It will maybe change in the future).
You don't even have to have "serious GB space" there is a Garbage Collection Version that reduces the Node size dramatically; the future "IronTez" Implementation from Nomadic Labs will reduce the required Space even further. More info on this here
It's cool to be a Tezos Baker (and to help the Network with decentralization) ;)