Fantastic ally on Leo Anderson, given it synergises well with his main ability

Main issue Leo has, is that eventually you run out of space for allies, which basically blanks your ability outside replacing allies with other allies, but with G-Men, as long as you keep a free slot for them, you can play them using Leo reaction and enjoy a 2/2 tanking (or possibly more with The Star) and +1 to all your stats for a turn for one resource, which will get your refunded during upkeep.

Just don't let them get defeated! I don't think the forced effect will trigger from the discard pile!

The new core doesn't offer a lot of skills for Silas, and this might be one of the more dangerous. Every time you apply it, you're risking 20% of your sanity. Then again, with the limited weapon pool, this is an excellent partner to meat cleaver. Take a risk on another check and then calm yourself with a crowd-pleasing ghoul decapitation. What Mystics like, especially when the Jim Culver ally's in play, is you can commit this for others and gain the "benefit" yourself. Agnes's ability is gated to once per phase, but this is a perfect way to deal damage to a foe in Mythos. And it's even a spell, which means Arcane initiate can fetch this for you.

The irony of this card is that you should be a tricky bastard when you use it. Cards like premonition (which leave play almost immediately), arcane initiate (who is sacrifice bait), items with uses that discard when they're empty... There's absolutely no reason to use this on an asset you expect to be in play by the end of the round, unless the agenda is going to advance from Doom anyway. Play it on something, have Dexter play another asset, and pick up the asset with doom. Huzzah.

In Arkham, the will of the universe can be truly horrid indeed, so it's best to subverted whenever possible.

This is deceptively useful in the core box. Because the card pool is so narrow, economic options are much fewer. So why not recur emergency cache? Especially for Miguel, who has a free event play action, you'll need a way to pay for the $2 fast events you cover the map in.

This is even more fun in survivors like Rita and Yorrick. Yorrick now has an easy way to get his events out of the trash with an asset. Rita can make sure she always has Belly of the Beast right before she evades. Wendy will like it because the more stuff out of her discard, the less horrible her weakness. And if she's particularly devious, she can get three copies of easy mark(1) even after she's spent them.

This is a fun new toy for survivors, more useful later in the match when your discard pile is big.

If the goal of the Survivor is to survive, this is one of the best allies ever released. Over an average 10-round game, Aleksey can heal nine times, and then take four hits for you in the final push. Without things like Solemn Vow in chapter 2, he's not going to be able to soak damage for the party... But some campaigns just pile on the punishment, and Aleksey can keep you alive. Ally is a competitive spot, and with access to chapter one, survivors may have other favorites. (For example Ashcan Pete and Madam Labranche, with the power to toss cards and the ability to draw them.) But if your goal is not to die this is a great investment, the earlier the better.