... and it tends to totally negate cursing attacks, especially in 2-player.
This part is just not true, I would say that you often want the curser as well as the Masquerade. The main reason being that putting a curse in your opponent's deck has a more immediate effect than trashing a card from yours (it comes into play a turn earlier in a sense).
EDIT: I'm not actually sure this makes any sense at all, probably depends on shuffles, someone should tell me if I'm talking nonsense here. So getting the curser usually helps you win the deck size war, though Masquerade does tend to negate the VP effect from curses.
I started thinking about this, so here's a list of my opinions about Masq vs. Junkers (I strove for completeness):
Witch - I say it's generally worth getting a Witch for the reason I mentioned before. The +2 cards can compete with Masq in terms of cycling, you will get to play the Witch as often as the Masq roughly (once you have it).
Mountebank - Very often worth getting as you dish out 2 junk cards instead of 1.
Soothsayer - May be worth getting if you have a good use for Golds, though I think Masquerade would indicate avoiding this card in the early game.
Torturer - Masquerade defends very well here, but it only "negates" Torturer on a board where the right call is Big Money. On an engine board you are still buying those Torturers usually (for the draw and the attack).
Sea Hag - This card is hurt a lot by Masquerade, in large part because you won't be playing the Sea Hag as often as they play the Masq.
Young Witch - Masq as bane makes Young Witch pretty bad, otherwise you still might want the YW at some point (like Witch, it is equal with Masq for cycling).
Familiar - Sometimes you can get 2-3 Familiars and just swamp your opponent in a couple turns, but this one is going to depend heavily on the other kingdom cards, you may need to skip the Potion to get key $4-$7 cards. I like pairing Masquerade with Familiar.
IGG - I would guess that simulators show Masq-BM (with 2-3 Masquerades) going for Provinces beats pure IGG rush. I don't know how Masq-BM does against IGG/Masq BM (could be another case of wanting to get both). Masq into engine should counter IGG pretty well.
Followers - Umm (running out of inspiration), Followers is still good because discard, definitely a case of wanting Masquerade + Curser usually. If the kingdom has strong enough draw, Followers will be a lot worse against Masquerade.
Ambassador - Masquerade can counter Ambassador quite well, especially if the $4s/$5s are important, but you usually still want to win that deck size war with Ambassador (often want both
cards).
Cultist - Still worth it because it dishes that junk so fast (cycles faster than Masq).
Marauder - Depends on how bad you want the Spoils, but Masquerade does counter the attack part pretty well.
Swindler - Hitting $5s with Swindler still awesome, the Copper->Curse is much worse. Often want both. Hitting Masq is pretty cool.
Jester - You silly goose, Jester is a gainer!!! Which I suppose means it is helped a little bit by Masquerade removing junk.
I'm not talking about Noble Brigand even though the wiki wants me to.
It's not uncommon for the Cursers to become more important later in the game as well, if Masquerade passes are becoming infrequent, or if your opponent will have a harder time matching Masquerade with a Curse in hand. Sometimes the couple VP or extra junk can make enough of a difference in a close game.
