2011 Certified pre-owned Legacy. Deal or no deal? Warranty?

I'm looking to buy either an Impreza or Legacy, and am wondering if this is a good deal. It's around KBB price but I don't know how relevant that is for buying a pre-owned Subaru, and my time for shopping around to other dealerships is limited due to not having a vehicle currently.

2011 Subaru Legacy 2.5i Premium.
21k miles
Certified pre-owned.
Warranty good for about another year.
Clean carfax.
$18810 after taxes, fees, etc
It was a lease vehicle, but all the required maintenance was performed, and the oil was changed every 6k miles.

I know that warranties are generally a bad idea, but since it was a lease vehicle, meaning the previous driver may not have cared about it's long-term health, is it a good idea? Subaru backs their Certified pre-owned vehicles with a 7 year, 100k powertrain warranty. Would that cover the things that a neglectful driver might cause to go wrong?

Thanks for reading, and any opinions are appreciated!
Kurt