Hmm... tough choice, because Apollo Justice is the continuation of the main story, but I personally thing AAI is the better game (also I love Edgeworth/Gumshoe). I would say that if you're planning on getting a 3DS and playing the next 2 games in the foreseeable future, go with Apollo Justice, but if this is just a passing fancy, give AAI a shot. I also thought the writing in Apollo Justice was way too self-serious for the Ace Attorney series, and found most of it extremely forgettable.

Also, if you play AAI, there was a fan translation of the second game, also a DS title, that was actually really well done. AAI2 is pretty high up on my list of Ace Attorney games so try that out if you can as well.

Apollo Justice is a more straightforward good Ace Attorney game. I'd even recommend it over AA5. Ace Attorney Investigations is pretty fun, but it does feel a little like fanfiction.

I'd say Apollo Justice since it's the continuation of the saga -- Ace Attorney 4, you could say -- and if one day you ended up with a 3DS, you'd be all set to play 5 and 6. Overall I probably like it more than Investigations anyway, though both are a delight. But between the two, I think AJ comes away with the most memorable characters and moments. That's how I feel about it, anyway.

The only major knock against Investigations is that playing it will make you sad that they never localized its sequel, haha

Investigations is a different kind of game though has many of the same elements. Apollo Justice is the same gameplay and structure as the trilogy, and even continues the story.

Investigations 2 is really good though, but there's no English release except for a fan patch.

I kinda didn't like either of them. They're fine, but they're also forgettable. Apollo didn't work as a passing the torch thing(I'm pleased that Phoenix returned on 3DS), and I can't recall half the Investigatipn cases. Voted for Apollo Justice.

I think they're both worth playing, but if you have to choose one, I'd lean towards Apollo Justice for the reasons the other people have mentioned.

Thanks for all the responses! From the feedback I have decided to pick up Apollo Justice. It seems like that`s the game people like the most and since I plan on getting a 3DS at some point it would be nice to be ready for those games. I will definetly put Investigations in my backlog though and get around to it at some point though.

@dudeglove: I actually played the Wii versions of those games (for some reason I don`t recall) which also had the extra DS episode in it (it was really good, maybe my favorite case in the series).

Apollo Justice is solid, and one of the prosecutors is a world-famous rockstar who just does lawyer shit in his spare time so it gets a lot of bonus points for that.

Investigations is my least favorite game in the series. It was a long time ago but I seem to remember the writing to be kind of weak.

I didn't like Apollo Justice that much, but I also don't remember it that well. It has its moments, and obviously if you want to play the 3DS ones it wouldn't hurt to play.

AAI is decent, not great, but I have to say it's Japan-only sequel (with a fantastic fan-translation) is one of my favorite games in the series.

Assuming you haven't played either I'd recommend Apollo. If you've played both I'd say go get a flashcart and load on the fan translation for Investigations 2, which is one of my favorite games in the series.

I mean they're both tied for "lowest point in the series" as far as I'm concerned, so I'm not sure I'd be able to recommend either of them.

AJ was essentially just "let's have a fresh start with all new characters... who are all just filling the roles of the older characters who were way better!". Investigations was just dull and forgettable (except for the last "boss" which takes like 5 hours to break through his dumb reasoning, and I wish I could forget that part).

Apollo since it introduces characters that are in the Dual Destinies. Also the music is sick. Probably my fav OST of the whole series.

I don't think I ever got around to finishing Investigations, and on the other had Apollo Justice is definitely one of my favourites. The final case in AJ is just outright bonkers nonsense and I love it, so that's definitely my vote.

Ghost Trick: Phantom Detective

Ace Attorney Investigations first, then Apollo Justice (that's more true to the timeline of the series chronology anyway). Ace Attorney Investigations is such a novel and interesting change to the formula that I think you'd probably enjoy seeing something new in terms of gameplay (with familiar characters, and some great new ones) instead of something new in terms of story (with some, but not all, familiar characters). Also, I have a very low opinion of Apollo Justice's cases, which are only really interesting in the beginning and ending (Cases 1 and 4 are great, 2 and 3 are middling to awful), so weigh that as you will.