I played this game when it first came out on the PS2, and I have no real experience with the series outside of that. This game has some of the best sense of humor I've seen for a video game. Which is mostly what it brings to the table today. I'm not saying the game is bad by any means, but please just keep in mind it came out on the PS2 and some of the mechanics and gameplay elements are a little dated. Hah, you thought I was going to talk about graphics, didn't you? Also, the controller mapping is a little bit of a nightmare, though it's fairly easy to get used to it once you play the game for a bit. I would recommend if you haven't played it before, play it for the humor and jokes, or the amazing voice acting talent on display. But the gameplay itself is a little dated and isn't going to impress.
Ultima IX is a bad game. From many different perspectives and layers, it is a bad game. Why? It has bad and lazy story-telling, poor level design, a clear lack of understanding for canon and the characters that were established in prior games and many technical problems. Now, I haven't played the version from GOG, so I don't know if they fixed the crashing problem that the original had. So I won't dwell on it too much other then to say that the original release was extremely buggy and would crash constantly. This game was put out by EA, and to understand what a death sentence that is to fans you have to understand what EA was doing around the time this game came out. EA in the 90's had this habit of finding smaller, profitable game publishers and buying them out. Once EA owned the license, they would then pump out games with that license with very little regard for the vision or intent of the original developers. Ultima IX is one of the best examples of EA simply cashing in the Ultima title so that they could make a quick buck. I could go on and on about how this game fails on every single level. The story is lazy and doesn't bother to even try to get simple facts right. Some argue that in a "meta" sense, they were appealing to casual gamers who hadn't played the previous Ultima games before. Hence the infamous "What's a paladin?" question. The reason I find such questions as that lazy and stupid isn't because of the fact that such questions are in the game (though you could make that argument), it's that it is LAZY. Don't make the avatar ask something so supremely stupid as "What's a paladin?" or "What's the Codex of Ultimate Wisdom?" Have someone else ask the Avatar that, and have him explain it. That way you have your training wheels explanation in your game, but it doesn't make the avatar look like the guy from Memento. I can go on and on. Seriously, they completely got the character of Lord British wrong, they ignored the canonical ending they gave Lord Blackthorn and turned him into one of the worst card-board cut out villains ever...and on and on and on. I've purchased every Ultima game on GOG up until this one...and while I am tempted to buy it now, I'm really hesitant because I just don't really feel like reliving all the betrayal. If you want a really thorough (albeit REALLY long) review, you could check out the Spoony review he did of the series.