I've got the Medela Swing pump - it's great but it is only a single. When the girls were in the SC nursery we used the pumps they had available which were doubles - again the Medela brand. They were brilliant.

Like Traveller said, I guess it depends on how much you are going to pump. I was doing it multiple times a day when the girls were in the Special Care nursery, using their pump at the hospital and then my own pump overnight to try and establish my supply and have enough milk for the girls at night when I wasn't there. Now I am using my pump once at night - I pump before going to bed and DH gives them that in a bottle at their late evening feed so I can get some sleep before the 2am-ish feed. It does take time to single pump though - I do 5 mins one side, 5 mins the other then repeat. I do think a double would be handy due to time and also I tend to leak milk out of the non pumping side , but I couldn't justify the expense of a double machine when I already had one.

I guess in answer to your question - I recommend Medela . Good luck with everything!