So far I've done very little grinding. You need to collect fuel and stuff to survive and progress but it's easy and plentiful. There's no mining for hours to get just enough fuel to get to the next mine. A quick blast with the multitool and you have plenty of stuff to do plenty of exploring.
You do need to keep yourself alive but I started out on a planet that was -40°C and I ignored my life support system and didn't die.
The first bit of the game which is essentially a training mission is about fixing your ship and getting a hyperdrive to be able to go out and explore. I did it in about an hour but I spent some time chasing a stripy weasel thing so you could probably get to the good bit quite a lot quicker.
Once you've got the hyperdrive, there's pretty much no rules. Explore, trade, mine, fight, conquer, it's up to you. That's the bit I love and what I wanted from Destiny. In this, I can go anywhere on any of an almost unlimited number of worlds without running into an artificial barrier.
It's not going to be everyone's cup of tea but I love it.
A slight majority of a statistically worthless sample size agree.