I played Armageddon for about a year. Before that I was a staff member in Shadows of Isildur.
Armageddon as an RPI takes a hit with the stock game mechanics often found in hack and slash games. The rigid choice of which guild your character is does not offer a wide range of customization that would be expected in an immersive game. Compared to similar games like Shadows of Isildur, Harshlands, Sindome, or Arx MUSH, Armageddon is severely lacking with its lack of a skill-based character generation system. This leaves the mechanics at a mediocre level at best.
The game seems to run on a DIKU codebase with features added on. The nice thing about DIKU is that it's familiar, on account of how popular it is in the MUD world. The programmers who work on the game seem very active but the game seems to have taken a hit with a couple of losses on staff.
One of the best features of the game is its emote system, which allows for the player to target other players and items with various symbols like ~, !, and more to print their short description out in the way they would see it. So if you do "emote nods to ~man" most people will see " nods to the tall, muscular man", but the tall, muscular man will see " nods to you". Very immersive.
The game world is very hyped up as being a harsh desert. However resources are practically infinite once you know how to get them. This leads to the harshness of the world being mostly imaginary (with few exceptions such as super-strong mobs outside the city). The city of Allanak is an interesting setting at first but once you realize there are no other options it becomes very confining. I would have liked to see Tuluk, which has more documentation for it than Allanak, but is unfortunately closed for play.
Unfortunately the community is not very good. Those who have posted reviews saying it is good are in the in-crowd of the community and probably see it from a different perspective. From the perspective of a player who has been around for almost a year compared to many who have been around five, ten years or more it is clear that the community is broken into tiers. Newbies are constantly ignored both in game and out unless they make an effort to please veteran players in some way. I was outright told that my character was refused a promotion because I did not consent to erotic roleplay with my character's boss. I have asked questions and been ignored or told to be quiet.
Following what was said above about the community, the staff tend to protect veterans and themselves and look at newbies as potential threats or alt accounts. While many do their duty seemingly quickly (Akariel, Nergal, Xalle, Cayuga, Shalooonsh) most others are slow to respond. The community tends to like staff that interfere the least, and by interfere they mean surprise animations, commenting on the forum and offering advice. This has led to a conservative staff base that is reluctant to change the game or go out of their way to do amazing things for players for fear of being criticized. I for one was pleased to see my staff animate for me. But it seems like the community drove out many hard-working staff members like Cayuga, Nergal, and Xalle because they either voiced their opinions too loudly or got burned out by doing things for players for no reward.
As this game is an RPI you would expect the roleplay quality to be top notch. However it tends to hang around the mediocre level at best. Most players are playing a character which is good, but many characters seem to have goals of the player rather than their own goals. Male characters in particular are often looking for erotic roleplay which makes it hard to play a female character who wants to use their time productively.
I have played for about a year and stopped in mid December with the holidays. I decided today that I would not be going back. This is bittersweet however as I can't say I didn't have fun at least some of the time I played. However most of the time it was unfortunately a slog. Many games are out there that offer intensive roleplay without the high barrier to entry imposed by the community or a lack of good game mechanics as imposed by the rigid skill system. I would suggest that you play Armageddon if you are interested in the setting but avoid the GDB (general discussion board), the alternate "shadowboard", or the Discord channel as these are places where the community is at its worst. If you must talk to people outside the game, keep it to the staff or to the helpers as they are mostly helpful.