Heh, the episodes aren't even that linear. Okay they follow a storyline of sorts, but you don't really get 'spoilers' or anything since it's… mostly historically based lol.
What a lot of people seem to really dislike is how the dub is (a lot) more offensive; personally I like it this way, it seems to pack more punches... <_<
France's accent was just hilarious, it reminds me of Allo, Allo (a British sitcom, where they did really stereotypical accents to represent people speaking in 'different languages', and as such, the 'Britishman masquerading as a French policeman' with a really, really bad French accent, getting words all wrong). His laugh is just perfect.
America is just absolutely spot on. Abnoxious, loud, and well, 'dude'.
Russia's accent is just too damn cute when he's being neutral. When he's terrifying, oh boy is HE terrifying. And lol, 'it make me pleasure smile'. That made me laugh for some reason.
The only thing they really messed up here as far as I can tell was 'Kol'- I'm not sure they knew it was intended to be a multi-language word. It's not that big of a deal to me, though. Some people liked it as 'killkillkill'. I didn't mind it that much.
Ukraine: She really does sound like a cry-baby older lady. It's strangely cute.
Belarus: 'Big brother, the doorknob that was holding us apart is GONE, isn't that nice?' Holy shit, that gives me chills.
China: I don't see what people are grasping for in China's voice. He sounds more like a dude than the Japanese version.
Japan: Perfectly smooth-and-serious. Love it! Also, 'respond Japanese way' part was just awesome.
Britain: Apart from the obvious mess-up ('SCONN', not 'SCOEN' xD) and a few unintentional Americanisms in manner of speech (t sounding like d), I really love the guy's voice. In their defense of 'SCOEN' though, it IS spelled kind of like it should be said that way.... IDK, English language is confusing sometimes.
ITALY: Now when I heard his voice first off, I didn't think 'Mario'. Well, Mario has a somewhat different range and delivery. These guys obviously have the same stereotypical accent, so go figure. I think he sounds adorable, in any case. Good ol' Hetalia.
Germany: Amazingly well suited voice, and the random German words popping up in a sentence were nicely done (und instead of and). His voice is very powerful, which suits this character swell. Especially when his 'soft side to Italy' comes out (Ich liebe dich, hee hee). Makes him sound so stiff and awkward, lul.
Now who could forget Canada? His voice is a very soft version of America's, which actually suits him to a tee. After all, characters do get the two confused. And Kumajiro sounds a little more like a little boy-bear here, I thought. Even a little terse with that 'Who're YOU?'. xD
..The only voice that kind of grated on me a little was Lichtenstein. It may be a typical anime trope, but I just can't imagine a voice that high coming out of a teenage girl xD;
Also Sealand... I THOUGHT YOU WERE A GIRL, DAMNIT