It's traditional MTG, no frills or unique online play specific to MTG: Arena.
Standard, Limited, Sealed Draft, Booster Draft, BO1, BO3 Ladder, Free Play, Challenge Mode vs friends.
Generous reward system and perfectly free to play. (In one block's time you can expect 168 free packs at minimum if you play each week)
Follows the current MTG standard competitive rotation.
You get wildcards in packs which allow you to craft whatever cards you want or need for decks. There's a "pity timer" for mythic rare cards every 24 packs.
This will be the successor to MTGO down the road as Hasbro and WoTC have announced a 10 million dollar esport plan.
I have been playing it for awhile now and highly recommend it to anyone who wants to get back into magic but not paper magic. It's much better than Hearthstone and is the grandpa of all these TCG games you see these days.