The original disappointed many PSO fans. This one doesn't. It's time to come back to Phantasy Star Universe.
However... SEGA mades some changes that many fans were disappointed with. The lack of content at launch and beyond for awhile, greater emphasis on grinding than its predecessor, the change in the combat system (no strong and weak attacks), the slower pace of progression and game being too difficult in general.
Many players left and those who were really loyal stayed behind and endured much. Over the course of the life of PSU, slowly SEGA did get the message and started making improvements. Game content was being released at a faster pace, changes to the game system to make it less hostile to a weak player and such but it wasn't enough.
Fast forward up to the present, Phantasy Star Universe: Ambition of the Illuminus addresses and fixes a great deal of the issues that were present in the game at launch and beyond.
Content wise, almost all of the content from Phantasy Star Universe have been released save a few miscallaneous items that haven't shown up in the monster drop list. Up to date there are up to 42 missions available for players to choose from not including the new missions that will be made available through updates in the near future. There are a flurry of new maps, monsters, items, Photon Arts, classes, weapons and bosses added with the expansion itself.
Though having new content is usually nice and all but what is important about Phantasy Star Universe: Ambition of the Illuminus is that it changes the game play by a mile compared to the original game.
Graphically, not much has changed with the exception of the inclusion of shadow rendering that was missed in the original and a broader resolution support as far as I can see. However the new maps and areas have greater detail than the original areas so it is small eye candy from time to time. It still has its Japanese styled looking player characters so really if graphics was an issue to you before, don't expect too much in the expansion.
To address the grind, all monsters have had their experience rates buffed, item drop rates were all increased, all missions now drop meseta more frequently and the amount dropped is now based on the amount of players in the party (the more the better) and all characters have had their offensive stats boosted significantly to the point where it plays out more like PSO. The death penalty was revamped so that players that die mid mission without a scape doll could be revived without costing the party a rank drop in the mission rewards.
SEGA also tweaked with the combat system to give it more PSO feeling. In AOI, you have something called Just Attack and Just Counter. The purpose of Just Attack is that if you time your attacks instead of button mashing, you would do a strong attack from PSO. Not only the strong attack deals more damage, it also helps regenerate your weapon's power points (used to execute Photon Arts). Just Counter is SEGA's new way of making evasion more useful. In PSO and PSU, blocking is based on your evasion stat aka EVP. The greater the stat, the better chance you can block against attacks. However many players lamented that the block generally breaks a player out of an attack combo and generally shunned upon. In AOI, when you do block an attack, with quick reflexes, hit the attack button and immediately you will attack the monster back with power equal to a Just Attack (Strong Attack).
The Shop system also received an upgrade itself. Now you can search for items and set conditions on price, item type and name of the item to ease the search for the item you want to purchase from other player shops. You can also view the item in question directly from your own room so you wouldn't need to make the trip to that player's room just to view their item and asking price.
Much of Phantasy Star Universe has changed since launch. Unfortunately with a market so saturated with massive multiplayer online role playing games its hard to find time to play them all. PSU was once one of those games though it wasn't even a MMO to start with. PSU is no more of that catagory but rather just a persistant online RPG that many people can enjoy casually and hardcore.
If you do decide to come back to Phantasy Star Universe, be sure to ask yourself if you do enjoy the hack n' slash genre or not. PSU is still a hack n' slash may not have the depth of gameplay some may expect. However if you did enjoy PSO or other similar games like PSO, consider the different versions of the game. Xbox 360 version requires the original to be played while the PS2 and PC versions do not (a mistake on IGN and many other game sites). At the same time the Xbox 360 version is cheaper but lacks an offline story mode unlike the PS2 and PC versions. The PS2 and PC servers are linked together while the Xbox 360 version has their own set of servers.
Personally, I do really enjoy PSU. Infact I'm playing it right now and happy because I found some really nice rares to give myself that sense of progression. Not to mention the game is a lot easier. Though I notice there are some short comings to some parts of the game but really, but what its been through before, the game has enjoyed a great deal of improvement and definitely fun to play. I would recommend anyone who enjoyed PSO to come back and play PSU now and see that this is the real deal that you've been waiting for.
Note: You have to play online to get the full experience. Playing only offline deprieves yourself and the game of a good experience.