There's a saying: if it comes in a kit, it's crap. Both of those are decent beginner products. You can do much better in quality, but you'll need to spend more for them. Here's a decent brush:

https://www.amazon.com/Princeton-Artist-Brush-Neptune-Brushes/dp/B00512BTPW/ref=mp_s_a_1_15?ie=UTF8&qid=1546978839&sr=8-15&pi=AC_SX236_SY340_QL65&keywords=watercolor+brush