What do you mean by hardest? I’ve heard that mentioned before but I don’t get whats difficult about the Pokemon games. Battle tower is hard and the elite four was quite harder in the ruby/sapphire/emerald games as oppose to the gold/silver/crystal which it was relatively easy. However, apart from that… it’s not that hard.
3v3 battles are fairly rare from what I remember. That, and there’s two types: Rotation and Triple. Triple is exactly what you think is; 3v3 with everyone getting a go at it. There is a bit of strategy to it, since pokemon on the sides deal less damage, and some other crap. Rotation basically has you choosing one of the three out and attacking whatever the opponent chooses.
Also, some good things:
-EXP reworked: Pokemon get more EXP in general now. Basically, if your Pokemon’s level is below the opponents’, they’ll gain more EXP. This can be pretty funny in the postgame when you kill something and a Lv.1 Poke jumps 20 Levels. However, the opposite also holds true; if your levels are too high (starts from >10), you start getting less EXP.
-Infinite TM usage: Yep, no more single-use TMs. Of course, this makes some of them harder to find…
-Awesome Music: Seriously, the game’s got some awesome tunes.
Only thing that’s kinda annoying sometime is the encounter rate for some areas. Most of the time, it’s ok, but in some areas, it’s ridiculous.
(Hint: Pack a lot of Repels for Chargestone Cave or you’ll rage hard.)
That, and the C-Gear’s fairly useless and drains the battery like hell if you keep it on.
I also, like an idiot, forgot to mention seasons.
I liked the soundtrack of the past game, but then I read that its battles are still slow. If there is a game of grinding, I want it to be quick-paced in its battles dammit. It might be the first Pokemon I try since the original, but I got a backlog and a dearth of time.
I got White, and I must say, I’m pretty happy with it thus far. A lot of the new 'mons are pretty neat. (Anyone have a Litwick? They’re adorable.)
Got White a few days ago. Loving the hell out of it. Just got the third badge and Throh is dominating all takers regardless of age, race, or religion.
Also literally lol’ed at the music when your Pokeman’s HP reaches critical and the beeping noise actually goes along with the music.
Just using this as an excuse to post some pretty funny comics I came across. The 2nd in particular always pissed me off in the original games. (And sadly, still very accurate.)
I never knew Tauros could learn surf… but omg, then second one is hilarious!!! xD
From other impressions I’ve heard it seems that you can actually encounter random double battles, and without the need to bring along a one time partner either. Which is good because they always have so many pokemon devoted to doubles support but outside of competitive battling (which is usually played on a level far beyond what most support options could afford you anyways) there’s virtually no double battles to speak of outside of a random trainer.
So OK, the first question is, which to get, Black or White? What are the differences? Yeah I suspect they’ll be minimal, but there’s always that odd pokemon you really want but can only get on one of the versions (besides the legendary ones of course.) I’m sure they’ll eventually come up with a Pokemon Grey, but why wait?
As for current likes/dislikes (this is based strictly on appearances for now) I’d say the lamest (even more than the Ice Cream cone pokemon) is the garbage bag one: http://pokemon.wikia.com/wiki/Trubbish (Wow, they REALLY must have been running out of ideas when they got to that one!) On the other hand, I really like the three-headed dragon (http://pokemon.wikia.com/wiki/Hydreigon) because of the way it evolves: it starts with one head, its second evolution has two, and the third has three BUT two of them are used as hands. Neat idea.
I’m kind of on the fence with the chandelier one (http://pokemon.wikia.com/wiki/Chandelure) I tend to find pokemon based on objects rather than animals or plants absurd, but damn if it isn’t pretty!
Trubbish is no different than muk/grimer or koffing/weezing from the original games. No real surprise there.
In terms of differences, white has white forest, black has black… something. White forest the pokemon are lower level and you can catch them. The corresponding place in black has higher level pokemon but I heard you can’t catch them. Other than that there’s different legendaries and regulars.
Black City has a bunch of high level (65-ish) trainers, but nothing to catch really. White Forest sounds much better but I don’t really know much about it.
Also, the experience rate changes depending on the level difference, period. There’s no point where it starts dropping off, it drops off every level no matter what.
Speaking of experience, I love Audinos. Relatively easy to encounter and loaded with insane exp? Delicious. Heck a level 1 Pokemon can earn almost 300,000 exp from the highest level wild ones (I think anyway, don’t know of any higher).
Could you guys please use spoilers… ^^ I haven’t played it yet and probably won’t for some time. Thanks! 
Sorry, we didn’t mean to spoil things for those who haven’t played the game yet. I’ve certainly been trying to avoid that which why I spoiler-tagged a comment about the game’s story above.
The rest of the comments seem to be more useful than spoilerish, such as which game you should buy eg. if you play the game more for the challenge you should play Black, and if you prefer to just catch Pokemon you should play White, based on the above comments. (I prefer to catch 'em all. 
)
Gila: Toxic Waste monsters = cool, garbage bag monsters = not cool. In my book anyway. (Just wait until I play the game and find out that Trubbish is really useful, ha ha. 
)
Look Garbage Bag is evolving! It evolved into a Trash Can!
SUPER SEKRIT!!! Should you trigger it’s evolution on Sesame Street instead it’ll evolve into Oscar the Grouch.
Only ever owned Red, then Ruby… good games, fun lite RPGs.
Don’t have the time sadly.
Oh, this just CRACKED me up!
http://nyletak.files.wordpress.com/2010/10/warubiaru.png?w=495&h=517
(And I disagree, I think B/W has some of the best pokemon designs ever.)
Personally, just use this:
The only other thing it probably doesn’t mention is that the 8th gym town also looks different. In Black, it looks futuristic, where in White, it looks ancient. Personally, White has better exclusives.
Those are the only exclusives? That doesn’t seem to make sense seeing as how there are over 500 of these damn things to catch now.
Hah, Pokemon White has the Cute Girl Pokemon and Black has the Gothic Girl Pokemon! LOL!
(Also, why does White have the Black Legendary, and White the Black One? It’s kinda confusing.)
But overall, yeah, I think I’ll go for White.