1) I have used the following: Medela Mini Electric, Medela Pump-in-Style, Avent ISIS (manual) pump. Since I BF 100% so I need to pump frequently, I can tell you that Mini Electric is no good. But Pump-in-Style is very good, but also expensive. Avent ISIS is very good too. Pumps are much cheaper in USA. For example, Pump-in-Style Advanced cost HK$ 4,200, but in the US, I think it is around US$ 240 only. But of course when you use it in HK, you need to buy a transformer to take the 220V and the HK electric socket. But I think you can buy the socket from the HK distributor too.
2) For the plastic problem, I think you are referring to the Bisphenol A issue. I think this is already cleared up, because Avent is saying that their product passes the safety tests.
3) Not sure, but I think the Bisphenol A only leaks out when exposed to high heat, like from a Steamer. For milk bag, since you won't be steaming it, I don't think it is a problem.