Recap:
I've been playing Ace Combat games since I was almost 6 years old with Ace Combat 2, I have play them all (including the atrocious AC for GBA), I have beaten them all in all difficulties and pretty much unlocked everything single thing in every single one of them.
I hate the fanboy term, makes it look like fans or followers of the game would praise whatever crap PA would develop, I am a big fan of the series, and as a fan I have seen the worse (AC GBA) and the best (vs Gault squadron in ACZ).
Ace combat 1 did the mechanic in basic polygons, AC2 started to do serious stuff with the Strangereal concept and a storyline in what it was essentially an arcade game, this aspect was developed so much that for AC3 there were 2 versions, one for EU and US that was very arcade focus, and a JP one that was very story focus.
From then on AC games focused on storytelling and actual game structure, narrative development and delivery, Ace Combat 4 built a world by which it could be free from using akins, thus getting more critical towards the aspects of warfare (mind you, the main plot of the story in AC04 is the story of a boy who's parent's were killed during the initial stages of a war, to then gain a living in a rather pitiful state with the very same person who produced his parent's dead).
From then on it builds on it's strangereal concept with AC5, which is a great example of narrative and delivery, but a poor example of characters and characterization, gaming wise the game became more complex and got a great cult of following due to it's campaign story, although is very flawed is very well delivered and both gameplay/story work in unison almost perfectly.
Technically I would have to mention ACX (produced by a different studio using the brand and the game mechanics, a PSP spinoff that was followed by the later ACX2, a PSP spinoff that introduced the real world instead of the strangereal).
There is also AC6 developed only for the 360, a huge slap to people who were eager to play that thing on their PS3, still, they didn't miss much apart from an over the top story that surpasses AC5 silliness in story delivery, gameplay wise it was a nice evolution from the normal concept that ace combat 04,5,Zero and X established, however it lacked in certain ways and the introduction of the g-turn mechanic made it worse for MP.
Then there is Assault Horizon, a U-turn from their PS2 philosophies from going from a story centric arcade game, to a arcade centric action game, dumb it down with the DFM mechanic it made a regular accessible game, thus trying to capture the COD crowd but failing to do so by breaking it's legacy (the Strangereal concept in general and the fame and experience that older games proceeded it).
Still, if there is something I love, something I think is the best thing in gaming IMO it has to be Ace Combat Zero: The Belkan War, an unexpected experience that captures everything, story, dialogues, characterizations, decisions and even truly sensitive topic, involved in a series of missions and tasks that were unique, and the last mission, which could go down in history as one of the best moments in media history, AC04 had a bombastic ending but Zero, and how it sums everything up is ... perfect.
So yeah, +2 cents.