The Amedas are the only closed system so you don't have to worry about contamination
If you are only going to use it occasionally, a manual pump will probably work. Medela makes a good one and a lot of hospitals as well as wic gives them to you for free. As far as an electric pump, the best one in my opinion is the Medela double electric (pump in style). They are fairly expensive though. A lot of pharmacies rent pumps as well so that may be an option if you are not going to be using it very often.