I do not recommend it as your first X game. I only played the very beginning of Terran Conflict and the entirety of Albion Prelude. Both of them have a very high focus on the sandbox elements: you'll be free to do whatever you want at whatever pace you want, which is really good for people already familiarized with the franchise but not for new players. On top of that, the in-game tutorials are really lacking depth — X3AP will have a brief flight tutorial and X3TC will have a brief flight and combat (against stationary targets) tutorial and no factories management, which is 90% of these games —. You'll also get a PDF manual as one of the goodies by purchasing it through GOG but I can't speak much about it since I disagreed with it and tossed it into a supernova. Maybe the answer for my complaints about the lack of tutorials is in there but I'll never know now. The story exists, I guess. As I said, these games have a very high focus on the sandbox part. Mods still work, which is great since I'm highly dependent on them for any game I play. Egosoft is one of the few companies to fully support modding, and you'll see that a bunch of old download links still work in their website forum (well... at least the links for the mods I wanted to install still work, maybe 1 or 2 were broken). Outside of that, a bunch of old guides and websites also still works — what comes to mind right now is Roguey's Website and the Complex Calculators that will save you some headache. I don't know... It's a really fun game that I've placed quite some time in. My only complaint is that it's not really noob friendly, even for X's standards. If you're searching for a game that allows you to do whatever you want, this is a good choice. If you never played an X game or wants something more story driven, I would tell you to try X2: The Threat first and see how it goes, since that one will have a more complete in-game tutorial and a proper plot development that will teach you stuff as you go.
It is not really an investigation game sinse you just click on stuff when your mouse cursor highlights and wait for things to happen (this is not a let down for me because the story seems kinda cool). And also, the manual mentions you can change how your character will talk to people (nice, normal, angry or user's choice), but it doesn't mention that if you choose anything that isn't "user's choice" your character will choose the questions he makes to the suspects. So it was only when I decided to change from "normal" to "user's choice" that I realised the game was locking me from a cig part of the gameplay (being able to choose what you will question the suspects for, which is really important because depending on what you choose, the conversation can end and the suspect will never talk to you again). The biggest problem on this game for me is that you really need to be very careful with the pictures analysis (really like the first movie, where Deckard enhances the image quite a lot), but in this game there will be really important clues behind other elements (when you find these important clues, that are behind other elements like walls, the game rotates the pictures around so you can see what you highlighted (it's kinda hard to explain, but without much spoilers, this happens at the first photo of the first crime scene). So I didn't found this important clue and got into a dead end on the third act, and this was when I decided to pull up a walkthrough and discovered I had to go back to the first photo from the first crime scene because I let a clue pass. So, if you're reading this and still want to play this game, I highly advise you to search for a walkthrough for your first playthrough, or be really careful while searching for clues on crime scenes or on the image analysis of the Esper machine.