Airport Express (2012) or Extreme (2011)?

Question

I bought the Airport Express today to use in a two floor house where everything's made of wood and most family members stay on the first floor.
During the summer we go in the backyard and play music while barbequing or swimming, but these are the settings where we'll most be using our internet connection.
I see that the Express (2012) has identical features to the Extreme (2011) in terms of network type, but how strong is one over the other in applications like I described? Will I be at an advantage using the internet in the living room or in my room (next to the computer room) if I have the Extreme?
What is the 'gigabit' port on the Extreme and why is that better than the Base1000 port on the Express?
And how fast is the hard drive connection on the Extreme? Is it enough to stream files?
Is it better to have the Airport Extreme for my purposes or will the Express do the job?

Answer 1

Their wireless ranges are likely to be very similar to one another, if not identical.
It is impossible to predict if one base station will be sufficient to serve your entire home. To extend your wireless range outside the house may require placing an additional Express near the area facing your back yard.
Gigabit Ethernet is another term for 1000Base-T, but the Ethernet ports on the Express are 100Base-T; 1/10 the speed of Gigabit. Despite the substantial difference, this is not likely to be a concern unless you want to perform large file transfers over your wired LAN. Wireless speeds are going to be the limiting factor. The same limiting factor will hold true for the hard disk USB port if you intend to perform file transfers wirelessly. Only the Extreme supports a USB hard disk.
The slower Ethernet port speed, the AirPlay streaming ability of the Express, and the fact that the Express has only one LAN port compared to the Extreme's three LAN ports describe the major differences between the two units.
Compare them here: http://www.apple.com/wifi/