Warning! This game is adressed to players who wish to have a competitive experience

Game modes
Master Duel is a competitive oriented video game focused on PvP with an exclusive banlist who's different from the OCG and the TCG, the game does not exactly reflect the meta of the physical version.
The game offers several modes :
-Ranked
-Casual
-Lobby
-Solo

Ranked mode is the most important and the one you'll probably spend the most time on.
The Solo mode is both a tutorial to learn the basics of the game as well as several archetypes but it is also a mode that tells the story, the themes behind certain archetypes.

Online events, updates
Master Duel is regularly updated, the game is late compared to the physical version which allows it to regularly release cards to change the meta.
Events take place quite regularly and are quite generous in terms of rewards. Master Duel offers loaner decks but these are rarely good.

Balancing and Meta
The part that frustrates many. Master Duel is very permissive about the viability of many decks. Maxx C is allowed and can lead to victory even with a pretty bad archetype, Red Reboot is semi limited, same for Change of Heart... Lots of cards are allowed (eg Predaplant Verte, Thunder Dragons, Heavymetalfoes Electrumite) so there is quite a lot of diversity of archetypes at your disposal.

That said! You still can't afford to play just anything. It remains a Free to Play game where building even a single deck will take you a long time. Therefore you cannot afford to play anything despite your first desire to get started and get your favorite deck before realizing that it is not very good or even very bad, thus causing frustration, loss of time and resources.

Thus I strongly recommend joining the Master Duel discord, Check Master Duel Meta[www.masterduelmeta.com] to know how your deck is played if it is it performing, get some good decklists.
(You may borrow a youtube decklist but this is at your own risk! Content creators do it for the views, the memes, the anime or anything else but the decks they present are most of the time gimmick/not optimal/even viable. Some don't have enough knowledge or experience to propose a very good decklist)

Free to play but pay to win?
The game is pretty generous when it comes to gems (the in-game money) when you create your account. The solo mode gives lots of gems. But the rewards decreases the more you play. However, events still give you plenty of gems, you can craft cards you are missing, dismantle cards you don't need (except from structure decks and the legacy packs). Pulls depend on your luck which may lead some to pay for more, don't do this, wait for the next event or play with what you currently have.
Purchasing gems is very expensive it is not worth it at all even with sales. The meta changes, your deck might be outdated you should always be up to date on changes.

Conclusion
If you like Yu-Gi-Oh!, seek to improve, face various archetypes this game is for you. If you want a more casual experience, an anime related game, play Duel Links.

On a more subjective note:
The game is good, frustrating at times just like most online games.
Very ergonomic in duel.
The soundtrack is beautiful.
The banlist is quite permissive.
Some decks are very strong but manageable, the only exception at the time of writing this review is the Tearlaments Ishizu deck but I think it will be nerfed.

I give this game a 16/20