I use the Target tanks as sleepwear, but I'm a bit too well-endowed to wear them out on the street unless I'm wearing a camp shirt over them -- too much bounce, and the white is also too translucent. Can't help you on the other brand; I took one look at the price and balked. Way too pricey for being subjected to spit-up all the time. BTW, I'm 5'4", and the Target tanks are quite long on me, my XL completely covers my tush.
Mostly I just wear ordinary v-neck tees and drop-cup nursing bras from Motherhood (they have a decent one for $16 that I have 6 of.) The V-neck makes it easier to reach in and work the clasps from the top, but a scoop-neck would work just as well. I just find wide scoops kind of revealing at the moment.
PS: I prefer the My Brest Friend pillow to the boppy, when your back is killing you it's possible to briefly stand up still wearing it, so I found it easier to position. Generally you won't need a pillow anymore by the time baby is about 3 months; those are only important at first when kiddo is too small to reach from your lap, and when your back is not yet used to the arm position.