When it comes to fans there is a wide range of choices. From manual to electric, pull or push, single or dual. Each has a specific and each a draw back and gain.
So a little about the differences. First with electric fans the differences between push and pull are the easiest to describe. A pusher fan sits behind the radiator (nearest the front of the car) and will draw air from the front of the car to "push" the air through the radiator on to the motor. A puller sits in front of the radiator(nearest to the firewall) "pulling" air from the front of the car through the radiator and on to the motor.
Also with electric fans you can have a single or a dual fan. There are a few reasons for this. Typically one fan is for your a/c, cooling the compressor and the other is for cooli g the motor (both may work in tandem to achieve this). Is two better then one? Not necessarily, as long as the fans is correctly sized. One fan can draw far less current then two freeing up hp by keeping amperage higher. Also one fan can be used for both the duty of cooling the a/c and the motor if properly place and wired so.
Manual vs. Eletric fans.... manual fans are pretty much a thing of the past. While they make aluminum blades to lighten the weight. They are still rotating mass dragging down your motor and the are severely inefficient coolers. Anytime you can swap out a manual fan for an electric counter part I highly recommend it.
Now brand wise its dealer choice. Everyone has their personal favorite. Mine is flex-a-lite I've used them on all my car with out issue. They also make a great slim line fan that is reversible which makes it idea for custom jobs where space is an issue.
On our mustang we're using their single slim puller design. To save space and in case we need to flip it to a pusher fan later. This one comes with its own easy to install thermostat with a/c switch for later when we install a/c. Also include are easy to use mounting brackets and a rubber surround so it can be made to mount flush on the radiator with out damaging the fins.
We start by mounting the fan (using the supplied brackets) to the radiator. Then finding a dry and out of the way location for the thermostat. After making a few simple connections using the wire and connectors supplied its all done and installed! Once we run the car. We can use the simple dial to decide what temp we want the fans to turn on at.