Always liked the Ace Attorney series, and hell the reason I bought UMvC3 originally was because of Phoenix Wright. (who I ironically don't main anymore.) I won't lie, I'm a fan of court drama and investigations, so I had a blast playing the first Ace Attorney game.
If you were to ask me a year ago, I'd have said I liked all games in the series. But looking back, I really don't. Aside from the first game (which holds a special place for me) and Ace Attorney Investigations (my personal favorite), I'm not big on the others. Justice for All was tedious and uninteresting for 3/4 of the game, and the last case, despite being perhaps my favorite in the series, doesn't save it. Trials and Tribulations, I hated the whole fey controversy, and Dahlia was pretty bland as a villain. So that rules out case 1, 4 and 5. Case 3 had a great criminal with a neat concept, but fell short because of...well it's self explanatory if you played it. I just hated it. Case 2 was the only good thing about that game for me. And Apollo Justice...I liked it better than JFA and T&T, I'll say that.
It also holds true for the prosecutors. Edeworth was cool at first and unlike Franziska and Godot didn't overstay his welcome, but it's primarily thanks to Manfred von Karma. It also helps that he was the prosecutor before Manfred, so he didn't feel underwhelming in comparison. I hold Manfred as the best prosecutor in the series, as he was the only one that I was literally intimidated of, and the only one that actually felt he was much more powerful. The guy was literally unstoppable until the end. The idea of facing a legendary prosecutor was genius that counters your arguments and controls not only you but the judge as well was genius, and the new prosecutors were just completely underwhelming in comparison. Yep, I didn't like Franziska and Godot as prosecutors. I liked Franziska better than Godot though, because she didn't have a completely cliche backstory. Klavier (...I forgot his name. He was forgettable.) was the worst, though. I don't want the prosecutor to be buddies with me. There's a reason why you don't face off with Edgeworth anymore.
The reason I like Investigations the best though, despite the glaring flaws, is because the whole concept of it is much more appealing to me. Although I do like the court room, I much prefer detective investigations. (I do hope to be a detective at one point, so I'm probably biased.) I had the most fun playing that game and I really enjoyed investigating. I always felt the investigations part in the main series wasn't fleshed out, but they fixed that in investigations and made it its own game. Not once in the game have I ever felt "I miss the court room". While it's true the game was ridiculously easy, I actually had fun solving the cases, pinpointing the criminal and find clues and connecting them. I felt like a child watching Blue's Clues. I also really liked the story as well. It didn't take itself too seriously (Trials and Tribulations...), and if anything felt comical and charming. (Alba's rebuttal was pretty much a parody of the series' "final bosses", with the ridiculous excuses and dragging. I loved it.) That was backed by how colorful the characters were. I felt, personally, that Investigations' cast was the most fleshed out and varied in the series, and they were just charming and lovable. Helps Gumshoe was at his best in this game, too, being my favorite character and all.
That said, as visual novels, there are much better games out there on the system. But calling them visual novels seem...wrong. AA is a point and click adventure where its main strengths lies in its characters and over the top silliness, and not it's narrative. To me, it's very similar to Metal Gear Solid in that sense. Though I feel Shu Takumi made a superior game in that sense with Ghost Trick (I like investigations better, still), but the series is definitely worth a playthrough by anyone. If if it came down to it, however, in terms of story-focused games on the DS (and in general), I'd choose Hotel Dusk any day.
