I have been playing a lot of Dungeons & Dragons lately, both with my brother's group (an online group, since the players live in different states), and among my own family.
With a large family, I run two different campaigns, one with my wife and my 3 oldest children (who are 21, 14, 13), and one is the "younger group", ages 11, 9, 8. And my 4-year old daughter, Lizzy, always insists on being at the adventuring table. She likes rolling the dice for the Dungeon Master. And she also insists on being in the party. Her D&D "miniature" is actually a toy dinosaur.
A couple months ago I discovered D&D Beyond. Officially approved by Wizards of the Coast, and programmed by Curse, it is a record-keeping system for players and Dungeon Masters. The DMs can create campaigns, and invite players to those campaigns. The DM can invite players into their campaigns, and share the manuals that they buy (electronic versions of the Dungeon Masters Guide, Player's Handbook, etc, pretty much all the manuals and adventure publish by WotC).
There are subscription prices for players (Hero's Tier) and Dungeon Masters (Master Tier). If you have a subscription to the Master Tier, that is what allows you to share the content you've bought with your players.
So how do I like the D&D Beyond? It makes some things very easy, such as rolling up/leveling up characters, because it is all done with a step-by-step process. I also like the electronic version of the manuals. They allow for easy searching, and it is a lot easier to have all the books available on your laptop or iPad.
Downside - to unlock the the content on creating characters, and to have electronic access to the monsters/etc, you have to buy the electronic versions of the manuals. There has been a bit of griping in forums about having to rebuy the manuals to unlock the content, after players had bought the physical manuals. And they cost a bit, for example $29.99 for the Sword Coast Adventurer's Guide. It cost $39.99 for the physical version, but $30 could still be a lot for some folks.
The best answer I saw to this in D&D Beyond's forums is that you have to think of D&D Beyond like a hobby shop. Curse, who programmed D&D Beyond, is not the same company as Wizards of the Coast. They are selling (reselling) content, and D&D Beyond has to be able to make money to offer services like that. You can see the thread HERE.
For me, I am happy to pay extra for the digital content. After all, anyone who produces a physical good, or an electronic service, has a right to be paid for their services.
For anyone who wants an electronic way of tracking the characters in their campaigns, or to have electronic versions of the game manuals (I think D&D Beyond has the only legal electronic copies), I happy recommend the service.