I currently own a 2012 Escape Limited V6 AWD and owned a 2006 Mercury Mariner V6 AWD. This basically represents the 1st and 2nd generations.
Both are great cars. The V6 is a good motor. The 1st gen have a 4 speed auto and the 2nd gen have a 6 speed auto. The 2nd gen has been tuned for more power and feels much more peppy. And with more gears, it runs quieter at speed because it's spinning fewer rpms. I also believe the 2nd gen has some additional quietness built in.
The AWD is really good. The system engages the rear at every acceleration- wet or dry, wheel spin or not. It then fades it out as speeds increase and is typically FWD by 35-40 mph. I've never been stuck. I've never been pointed in a direction I didn't want. My 1st gen didn't have traction control and even still behaved quite nicely.
Both vehicles are solid. No squeaks or rattles. The suspension is firm and quiet (although my dad has a 2011ish Mariner and has some kind of noise in the front on occasion).
1st and 2nd gens have the lift gate window that opens- I believe it's fixed on the 3rd gen. I like that feature. The weather seal in the 2nd gen is known to leak which then causes the hatch unlock mechanism to fail (I replaced both this spring). Good replacement video in YouTube by a guy named the FordTechMackuloco.
As far as gas mileage, 18 in the city and up to 25 on the highway.
The rear spark plugs on the 1st gen are a pain to do. You need to remove the intake manifold. But I could still probably do it in about 2 hours. I haven't done the plugs on the 2nd gen yet.
A good Escape forum is escape-city.com. This subsection is pretty much dead on this forum.