I started playing this very shortly after its release in Japan - that was back in february of 2016, at the time of this writing almost 2 and a half years ago. And I'm still playing it, but I'm pretty much at the final boss so it's a good time for me to write my review.
The fact it took me years to beat this speaks for itself. This definitely is a weak title. It's ironic that I'd never recommend this to someone who's never played a game in the series before, because you can tell the devs went out of their way to make this more accessible to a wider audience.
As far as JRPGs go the Shin Megami Tensei games were always a bit odd, with their very own identity that made the games unique and interesting. SMT IV Final retains most of those unique elements, but the game heavily expands on the partner mechanic that its prequel introduced to the series. Instead of fixed partners you now have a whole party following you along, letting you decide which should support in in combat. This makes the game quite a bit easier because you get another free turn with free healing or protection against status effects if you so desire. Aside from that it's the same old press turn combat that lets you recruit and fuse demons to fight at your side. The battle system is not where this game fails at, as it's as good as ever. The only problem I have here is that some specific random encounters can take annoyingly long due to enemies high HP pools in the end game, and there's some enemies that can come in waves of up to four in a row.
Shin Megami Tensei IV Apocalypse jumps the shark with its story and pacing. Many of the characters are well written and the story may have its moments, but overally it's not very interesting plotwise because the overall direction of the story becomes clear early on. From that moment onwards the game just keeps looping through the same events and similar plot developments. The pacing of this game is mission based: you always follow main quests that send you to places, returning back home or to a based afterwards where you soon obtain a new assignment. In between of doing these missions (or meanwhile as you're doing them) there's also a constant stream of side quests to follow. Most of those are fetch quests that only serve to ruin the game's pacing even more. Some of them have their own storylines, but even those aren't super interesing. Few quest lines lead to extra bosses, but none of them are anything compared to the main story's end bosses.
The real side content is locked behind DLC. Can't say I'm a fan of that. There's a bonus dungeon with a randomized layout featuring a couple of side bosses, but there's no real reward for clearing that place - unless you purachased the DLC pack that allows you to revisit more difficult loops of the dungeon where the bosses start dropping the best equipment in the game. Stuff like this really shouldn't be locked behind a paywall.
Like all games in the series there's multiple endings to this one. Unlike its prequel the ending isn't decided on an invisible stat anymore thus the game let's you choose your path freely. Out of 4 endings, there's however only 2 worth the player's time. The traditional law and chaos endings are only in the game for tradition's sake as they cause the game to end prematurely. The neutral endings are much better than their counterpart in the prequel as they pursue a plot line that was left out before. This may all sound good, but the game actively tries to push the player into ignoring the law and chaos endings. Your party members constantly talk about choosing the neutral path. Literally breaking the fourth wall and ruining everything this game could have been.
At least the graphics are great for a 3DS game. If you played the original SMT IV you know what to expect because this one's running on the same engine with lots of reused assets. The soundtrack is original, but just as great, if not better, than it was in the direct prequel.
The bottomline is... Shin Megami Tensei IV Apocalypse isn't really all that good. I wouldn't say it's bad though. Definitely not the SMT I'd recommend for newcomers. If you've never played a game in the series before you're better off getting the prequel or the recently released remake of Strange Journey (also on 3DS). Apocalypse is really only good for fans that wanted more out of the prequel, which its endgame delivers for those willing to purchase the DLC. Fingers crossed that SMTV will be better.