A great game that is no longer the end of the series but could've been a great one.
The storyline alone is magnificent. If you're the kind of guy who wants a war game without it being too war-ish then Jak 3 is the game for you. It has a huge World War 3-like feeling. In Jak II it was much the same but it doesn't feel like it until the game's climax. Here however it's a four-way war between Jak and co., Metal Heads, citizens manipulated by the sinister Count Veger and evil robots led by Errol.
If you want to take a break from the war then just go out in the Wasteland. I gurantee you this game will make you feel like how wars should be: just stop when you feel like it then go on from where you left off. You can do it anytime.
OK admittedly you can't do it right away, first you've got to earn the right to do so but when you do you'll be glad you did. Also one of the main things games do that sometimes earn it negative reaction is that it shifts the main villains too quickly. When the game kicks off it's apparent Veger is the main bad guy but, without spoiling too much, eventually Errol is the main villain. If there is a single game that changes villains masterfully Jak 3 is it as they steadily do it just right without making Veger fade.
As far as gameplay goes it's great. It's also not as hard as Jak II but not as easy as Jak I/Jak & Daxter. Rather it's easy enough to not be frustrating but hard enough to challenging. Also in case you're the type of gamer who enjoys an epic climax then Jak 3 is also for you. All video games should end the way Jak 3 does: one final battle in the overworld.
Speaking of overworlds, the Wasteland definately is one that you'll enjoy. Take Banjo-Kazooie's memorable overworld that changes textures fittingly and mix it with Jak II's memorable overworld of Haven City and you've got the Wasteland.
Overall Jak 3 is an instant classic and I suggest buying it now. Don't buy it today, buy it now.