My preliminary thinking is that Margrave is probably the strongest card in Hinterlands (besides perhaps Border Village). It's the Council Room + Militia combo all in one card- obviously not with quite the card draw of CR, but do you really mind for only a $5? And yet I don't think it belongs any higher than honorable mention as a $5 Attack (certainly displaces Rabble/Jester though)- chained Torturer is more disruptive to your opponent, and Minion counters it perfectly.
I have yet to buy Jack of All Trades, and have so far been of the mind it's really, really weak. The problem is that its various functions trip over each other and conflict. Gaining a Silver is not something I'm usually excited about (and doesn't do anything for this turn); the trashing really only works on Estates and you have to do it after you draw, so again it doesn't help your current hand; the "draw up to 5" bit looks like it could combo with stuff like Festival/Hamlet/Oasis, like Library or Watchtower, except that: a) the draw power is less than Watchtower, probably weak enough to doom consistent combos, and b) if you're getting all this Silver you're not going to be able to chain your Jacks, because they'll just draw you Silver and Copper that you can't get rid of. I've avoided it every time, and have so far done well against opponents that went for JoaT. Perhaps I'll be proven wrong?
One exception to the "I don't like getting Silver" general rule was a cute Trader/Stables game I played yesterday: Trader your Estates into two Silvers, buy lots and lots of Stables and leave your Coppers around for discarding. No Gold necessary, five Provinces (and maybe a Duchy, I forget) by turn 15. Hi-yo Silver!