Hi there. If you take it easy with the pumping (not too hard, not too long/frequent), you should be fine. Also, I think I was the first one on here to bring up the ring marks that stayed lighter than my normal skin color. I started spacing out my sessions more, and it basically fixed itself (massage of the marks helped a lot too). I also use a ton of poster tack for padding my domes (about an inch wide and a little less than an inch thick), which leaves me with barely any red ring marks after pumping. Figure out a good padding solution that works for you early on, and the marks shouldn’t be a problem (among your choices: poster tack, pipe insulation, camper mounting tape, yoga mat, NB foam rings).
If you ever do pump a little too hard, the little red dots (broken blood vessels) can be cleared up even quicker by using some cream or gel with arnica in it. Especially in the beginning when your breasts are getting used to the pressure and you're figuring out the appropriate amount of pressure, you'll probably get the dots at least once. I've been using NB for about a year and a half and I haven't had any red dots in well over 6 months, so I think a lot of it is just your skin and tissue getting used to the pressure.
I don't think it would affect your ability to breast feed some day, and I'm sure if you email Lucy she'll be able to answer that with more confidence.
Noogleberry definitely does work for the majority of people who stick with it, so if you're prepared to spend most of your days pumping for a couple hours or so, then you should have great results. Good luck if you decide to get it!