Attribute is naturally compared to the more mainstream party game Apples to Apples (below, A2A). I consider Attribute a much more fun game and have listed the ways the differences create a more enjoyable experience below.

A rules summary is available here. The "revised" scoring is easier and more intuitive, but penalizes players who happen to draw green sheep. The "original German" scoring is definitely more fair but a little harder to explain. If people want to compete in the score, they'll probably want to learn German scoring. Otherwise the standard scoring will average out over the long run and probably be just fine.

Fewer Bad Cards

In A2A, the adjectives are sometimes pretty specific and despite the fact that you have seven cards in your hand, sometimes nothing really seems to fit. Furthermore, there are some really terrible nouns (Dust? Creamed Corn?) that fit only a select couple of adjectives ("boring", "banal"); and some cards relating to specific people that not everyone will have heard of.

By contrast, the Attribute adjectives are broad, applying to many things, and the fact that you might have to come up either with a good match or a poor match makes things even better. Despite a hand of only four cards rather than seven, you will more often feel like you can make a good choice.

No Rejection

I get enough rejection in my personal life to have to deal with it in my party games too. Not that I am bitter. But in A2A, it's frustrating to have a good match you were proud of rejected for no good reason. (Adjective: Horrendous. I play The Black Plague. Judge picks Tomatoes because she doesn't like them on sandwiches.) In Attribute, other players stand to gain from trying to sincerely understand your play, so a good match is less likely to be rejected for no good reason.

New Friend-Friendly

With its highly subjective (at best) and telepathy-requiring (at worst) judging system, playing A2A with a group of people you don't know very well can seem like a frustrating maze of in-jokes and secret knowledge. How was I supposed to know Tom really really hates peaches? A2A rewards the player who knows everyone at the table. Although some knowledge of people's preferences is useful in Attribute, it's much less critical than in A2A. And there's still a period for banter in between rounds so the new person can learn about the group and figure out what's going on.

This is a double-edged sword, of course, and there are definitely folks out there who like reading their friends' minds. If this is you, well, go out and buy A2A if you don't own it already.

Natural End

"It's not about winning, it's about having fun, so we won't keep score, we'll just play until we're tired of it." A noble sentiment! Unfortunately this means A2A tends to overstay its welcome because people have to get really sick of it before they take the effort to stop. Attribute has suggested number of times around the board (rather than racing to a certain score--less like competition) and a small enough deck that you can play through once and then say the game is finished.

Twice As Many Decisions

Rather than just choosing or just judging, in Attribute you both choose and judge every round. As someone who enjoys the decision-making aspect of games, this is a strong appeal of Attribute over A2A for me. The fact that you have to be first in the judging round adds an extra layer of excitement and tension.

More Portable

There's no reason Attribute shouldn't fit in a cargo pocket; even the somewhat overproduced, overboxed Z-man edition is easy to carry around. A2A takes two hands with its big box and zillions of enormous cards. I normally wouldn't bring this up in a game review but as a party game, you might well also be trying to carry soda, cookies, chicken, whatever and arm space could well be at a premium.

So why is A2A so popular? Well, Attribute has a couple of qualities that might be seen as flaws. As you can probably tell from my prose, they are not the kind of things that mar my enjoyment!

Can't Play It Blind Staggering Drunk

Being falling-over incapacitated drunk should minimally impair your A2A playing ability, especially if the other players are in a similar state. Although I have not tried it, my estimation of Attribute is that enough judgment is required that it wouldn't work very well impaired.

Dexterity And Reflexes Required

This is the most sincere of the negatives. There is a snatching/speed element in Attribute that can't really be eliminated. It's nothing as potentially hand-bruising as Jungle Speed or Egyptian Ratscrew, but some players might not like it. Speed-wise, A2A has only the stipulation that the last player doesn't get to play a card, but this is easily waived (especially if a older/slower/whatever player asks) and in my experience often is.

No Power Trip

In the judging round, A2A gives a great power trip to the judge. They get to slowly cast aside the submissions they find unworthy, and some players seem to really get off on this. In Attribute, the judging has to be quick. If you really like slowly telling people their ideas aren't good enough for you, Attribute won't give you a forum for doing that.