(WIP)
Who likes complicated cards? I know I do. Some are complicated purely in mechanics, and others are complicated in how to play it properly. Advisor falls into this latter category. At first glance, it may seem weak - why should I let my opponent choose what I draw? But with proper use, it can be quite effective.
What does it do?Advisor is a variant on Laboratory in much the same way Envoy is a variant on Smithy. It reveals three cards from your deck, and your opponent chooses which two of those you draw. After that, you're free to play another Action. It falls firmly in the category of Non-terminal draw, just with the added twist of player interaction. As this effect is rather obviously not as good as an actual Laboratory, it's cheaper, making it a possible opening card.
How should I use it?A good point of reference for Advisor is Menagerie, as they require almost completely opposite decks to function. Menagerie requires a deck with high diversity (or at least a means of discarding duplicates from your hand), while Advisor requires a deck with low diversity. Think about it - if you reveal an Estate, a Copper and a Hunting Grounds, obviously your opponent is going to make you discard the Hunting Grounds. But if you reveal three Silvers... you get the gist. Advisor likes decks with, if not low diversity, than at least low diversity in card power - decks with multiple copies of cards of similar strength. To this end, Advisor really likes other Advisors. +2 Cards is still +2 Cards, and a barrage of Advisors can still bring you up to $8, even if it is through all Coppers. Similarly, Advisors like heavy trashing. If you have no junk cards, you won't care what's discarded to Advisor.
Another good point of reference is Warehouse. Yes, Warehouse decreases your handsize, but the key difference I want to talk about is that Warehouse lets you choose what to discard, while Advisor lets someone else choose. With Warehouse, you'll be discarding Coppers, Estates and useless Actions, while with Advisor, you'll be discarding Golds, Villages and terminal draw cards. So if you chance to trigger a reshuffle mid-turn, with Warehouse, you've now screwed over your next turn, because your deck is now full of your worst (or least useful) cards; with Advisor, there is no screwing - your deck is now full of some of your best cards in high concentration. So an Advisor player doesn't mind as much if they trigger a reshuffle, though if you have fewer than three cards in your deck/discard, you should probably stop playing Advisors, since you'll never draw that last card.
Remember that the two strengths of Advisor are 1) its cheapness and 2) its cycling power. You can get lots of them, and cycling through three cards, drawing two of them, is usually very nice. En masse, your opponent just won't know what to discard half the time, and what they make you discard will often not matter, because you'll still get two decent cards anyway.
What works well with Advisor?An engine of just Advisors can function quite well - a deck full of Advisors and Silvers will be quite good at purchasing Provinces. However, an Advisor-BM deck runs a very high risk of stalling after the first post-greening reshuffle - once you start revealing two Victory cards to Advisor, you're somewhat screwed. To that end, keep filling your deck with Advisors and Treasures.
Advisor also does well as a precursor to a better engine. Open with Advisor and Silver, and use your expanded hands to start picking up engine pieces - Border Village and Stonemason are very nice for this, as they don't require you to rely on your Advisors to draw a +Buy card. Once you've started your engine, you can trash away your Advisors - Remodel them into engine pieces or Golds, or Stonemason them into Silvers.
Advisor does not do well with "key card" strategies. For instance, if there are no Villages on the board, but there is Monument or Goons, Advisor would be a terrible choice, as you would always be forced to discard that key card.
There's a certain amount of synergy with any card that likes large hands. Secret Chamber is decent, as it's crappy enough in general that your opponent probably won't make you discard it. Bank is also nice, but it is expensive, your opponent will most likely make you discard it, and it doesn't come with +Buy.
How do I counter an Advisor deck?Be aware of what your opponent has already played this reshuffle. Not all Advisor reveals will be obvious Estate-Estate-Gold type deals - if they reveal two Hunting Grounds a Farming Village, you have to consider whether they have the Actions in hand already to play both Hunting Grounds, or if they'd be drawn dead without the Farming Village (to this end, Advisor players should avoid any card that makes them reveal their hand). Like with most things, junking Attacks are very useful here, as they help narrow down the possible "good" options revealed by Advisor. If there's one or more junking Attack on the board, you should probably reconsider buying Advisor.
Synergies:*Any homogeneous strategy
*Transitions into better engines
*Cards that like large handsizes
*Trashing
Anti-synergies:*Opponent's junkers
*"Key card" strategies