Lines really matter in pitching and flipping, or you'll gonna get broke off in the cover.
The standard for pitching and flipping is 20# test. If the cover is light, you can probably manage on 15# but if it's heavy cover you'll want at least 25# test. Otherwise, you'll be losing those big bass.
Berkley Big Game fishing line has been lucky for me in the past--tt's a great line with excellent knot strength, castability and resistance to breaking. And, I think i'ts pretty reasonable priced!
My number one line concern is the type of cover I'm fishing around. Most of the time I'll use 20 pound Berkley clear. For cover that is dangerous, I'll use Flora Carbon in 17 or 20. In sparser cover I'll step down to 14 lb. Berkley in clear. I know I tend to go heavy, but in my waters, you've gotta.
My buddy always uses 10lb Stren Original clear blue fluorescent line for jig fishing. It is quite visible above the water and aides greatly in my seeing what's happening with my line. I've also used Berkley Vanish Transition which is a fluorocarbon line that is a very visible gold color above the water and easy to see, which is great for jig fishing.
I highly recommend using clear line because visual line detection is such an important part of the strike.