My 2003 Escape had a 3.0L V-6. It was a very peppy engine. The 2008 Mariner Hybrid has much poorer acceleration by comparison. The Hybrid gets about 27 MPG vs 23 MPH with the V6 in the Escape. A Mercury Mariner is essentially a Ford Escape with some nicer trim options. It's a reasonable apples/apples comparison.
The Hybrid also puts limits on availability of certain electronic accessory add-ons and pretty much eliminates any consideration for towing. I had outfitted the Escape with a class II hitch before we traded it.