Obviously the hatchback shape of the new Impreza will appeal to people who need more utility than a typical sedan offers. The problem is the fact that it looks so mainstream, to the point where it won't stand out. Plus the design was executed in an odd way, almost as if Subaru made their interpretation of a Corolla hatchback. The '02 Impreza wasn't the greatest looking car, but it definitely stood out since it was a unique design, plus it was quirky in a good way.
I wouldn't really call it a sleeper, especially with its competition today. When the WRX was first released in the U.S., not too many people knew what it was, and 227 hp and 217 lb.-ft was enough to jump ahead of most cars in its price range at the time... Mustang GTs, Acura RSXs, etc. Nowadays, it has a bigger engine that isn't rated much better (though it is torquier), and will get slaughtered by today's Mustang GT and all of its numerous variations along with newer competitors like the Mazdaspeed3, Dodge Caliber SRT4 and the upcoming Mitsubishi Lancer Ralliart (rumored to have 260 hp and the entire AWD system from the outgoing U.S.-spec Evo IX).
I definitely think that the Evo X is MUCH better looking than the new STI, but due to the new Evo being so much heavier as a result of its added stiffness and safety, it has been shown to be slower than both the Evo IX and the STI since the modest power increase isn't enough to give it an edge. The '08 STI's straightline acceleration numbers are at least as good as the old STI's, but its handling is a lot better (Edmunds.com recorded a slalom speed of 72.0 mph) as well. The Evo X has achieved really good skidpad numbers (0.99 g stock, which is no joke), but it's not enough. Best Motoring, a Japanese television show about cars, tested the Evo IX, Evo X (one 5-speed manual and one 6-speed dual-clutch), '07 STI and Skyline (or Infiniti G37 in the U.S.), and the Evo IX finished first, followed by the STI then the two Evo Xs. Plus, they recently tested the new Evo X and STI head-to-head on the Tsukuba circuit (race track in Japan), and the STI was quicker. It's really disappointing, especially when you realize that the U.S. versions will be even slower due to even more weight.