I am a ftm so I can't say for sure but I am going to get the kiinde system it is pretty awesome and their is no milk waist! They have some good videos showing the product.
My daughter has no problem switching between different brands. I like the evenflo advanced+ ones because the nipple has a built in vent the keeps her from swallowing air!
NUK is really good! according to the research I've done but I don't have actual experience yet. I'm also doing Medela bottles to go with the Medela breast pump, but honestly just make sure they're bpa free