Adequate Send-Off
The King of Fighters XI is the final (non-remake) game in the series that uses the same standard graphics and engine. As a result, SNK Playmore obviously made the game as best as they possibly could. Is it the best KoF? Lord no. But they didn't try too hard and do something stupid, like shove every character in the canon into the title at the cost of gameplay like so many others do on their final game on an engine (I'm looking at you, Midway). Nor did they try to radically alter gameplay despite using the same engine.
No, what SNK managed to do is finish off this era with a fun game with crisp graphics. It doesn't best the pinnacles of the series such as '98, but it's worth the investment. KoF XI takes some of the best mechanics of the past (although, regrettably, it eschews the Striker system), and adds further gameplay tics such as Dream Cancels.
The roster, as mentioned before, does not try to cram in every character, but still does a respectable job of representing the franchise's vast cast. Some may bemoan the absence of series regulars such as Joe and Leona, or fan favorites like Angel, but honestly, with its eclectic mix of classics, old favorites (for example, Eiji appears for the first time since '95), newcomers, and first-timers to the franchise (such as Duck King, Silber, and Bonne Jenet), to the point that it doesn't really matter. It certainly represents SNK's history better than the sequel (XII, of course), and for those whiners out there that missed Geese, Robert, and Mai, their NGBC incarnations are intact, along with several other exports from that title. Originally, I had been against Jyazu and Hayate's inclusion (since Savage Reign and Kizuna Encounter are supposed to take place in the distant future), but they play so well that I found that they play so well that I just stopped caring about canon and focused on their gameplay.
A lot of members of the more hardcore crowd complained about how the PS2 version has enormous slowdown, but I haven't seen any yet. Granted, I haven't played the arcade iteration, so I can't compare the two, but I have been unable to come across anything that hampers gameplay.
KoF XI is well worth spending time with. Considering that it released in the U.S. at $15-20, and you can probably find it for $10 or less these days, it's not a regrettable purchase.