My DS is not gaining weight at the rate he should, so his doc has told me to supplement. I'm currently using an SNS at the breast after his usual nursing sessions to try and stimulate milk production (and a sleepy baby). I would like to get away from using formula in the SNS, but I can't afford an expensive pump. Medela is very much out of reach, possibly excepting their single electric "Swing" pump. Is there really that much difference in pumps? How do the Lansinoh "Affinity" and AVENT "Uno" pumps compare? I need a decent single pump on a very tight budget. Not worried about a dual pump as I'm hoping to use this to boost my production now, and then only occasionally as needed. I currently own a Lansinoh manual pump, but it's impractical. Does anyone out there have experience with multiple brands?