I have a couple of semi-bold predictions.
Count will be a card that is great if you can get it on a 5/2, or otherwise quickly; after that, it will largely shine in the late game and especially as the come-back-kid. You can use the return a card option like a courtyard to put back money or an action that might be more useful next turn, and then grab a Duchy still. I don't suspect that it will be a good card for Duchy rushes solely because it costs $5.
Storeroom, on the other hand, will be great for Duchy/Duke rushes. You can open Storeroom/Storeroom (or maybe a silver?), and as long as you have at least one silver in the top 9 cards (5 in hand and up to 4 from the first discard), then you are guaranteed $5 with a +buy to pick up a copper if you like. In that vein, Storeroom will rock Gardens games as it will let you get a Gardens and X every time you play it, and after the Gardens are gone, getting a Duchy or two Estates should be a simple matter.