I've owned 3 of these trucks, starting with a 1970 Datsun PL521 (my first truck), and a 95 Nissan Hardbody XE.
This 2001 base model XE 4 cylinder 5 speed is as good and reliable as the prior trucks.
I bought it in June 2008 and it had only 85K on it.
It now has 116K, and is barely broken in.
When I first got it, I repainted it the original Silver and installed a new set of Firestone A/T tires.
I've only performed basics maintenance and a tune up and a newer battery.
I've driven this truck on one long trip to MO to bring back a bass boat from my Dad's place.
It towed pretty well, even in the Western VA mountains. (3rd gear up hills)
I highly recommend this truck!
Reliability and gas mileage.
I average 21, mixed city and highway, and 27 highway.
I've never seen below 20 mpg.
It is surprisingly comfortable with the bucket seats.
The A/C/Heat works very well.
Honestly, for this year of truck, none.
The newer style Frontiers are larger and I wish they still made the smaller ones like this, which is why I chose it.