However, I am now considering pumping to donate for another woman who cannot produce enough milk for her baby.
What a wonderful thing to do!

I would see how you go with the Tommee Tippee first. My sister had this pump & she was EE for a few weeks, she did fine with the manual pump, she found it quite efficient. If you are pumping twice a day you might find it's fine for you.
If an electric pump seems better, I can only speak of the Ameda Purely Yours - it's the only one I have any experience with. I won't repeat my previous posts but I am very happy with it.