Indesit IWC 6125 S
Hoover OPH 716DF
The more power per year a device consumes, the less energy efficient it is, making it more costly over time.
Machines which use less water are good for the environment and can save you money in utility bills.
Hotpoint WMFG 8337G
Whirlpool AWE 8840
Front loading machines are good as you can use the space above and sometimes stack a dryer on top. In general front loading machines use less energy, using less water by only partly filling the drum and obtaining higher spin speeds which clean without requiring as much heat.
With a transparent door you can look inside the machine and see what laundry is inside.
You can adjust the height of the machine which means that if the floor is uneven you can level it out.
A faster spin speed means you can get things cleaner with a lower temperature of water. Using a fast spin also extracts water, meaning that the clothes come out nearly dry. Generally, anything over 1000 rpm is very good.
Machines with a load sensor can weigh the load and adjust settings accordingly. This means you don't have to feel as guilty about doing a smaller load as the machine will use less water.
With a wider range of programs to choose from you can be more specific and choose the best, most economic program for your needs.
More weight capacity helps if you want to wash something heavy like curtains. A traditional household machine can hold around 6kg, so with a machine much bigger you may waste energy using it when only half full.
With a delay start option you can schedule the machine to begin at a later time. You can also set the machine to wash at night if your electricity is cheaper outside of peak times.
With a bigger drum you can fit in larger items such as duvets, or do a big load at once.
The machine will let you know when it is finished with an alarm or even by playing a tune.