Myself I always used and always recommend the liquid waterproofing, the are many brand, every contractor will recommend on one he has good experience with, I believe most are good product , if not, we will not sale or buy them.
In regard to the sheeting membrane, use it once, and will not use it again, extra time/labor and not cheap at all. Apex $120.00 for standard shower 3’ x 3, x 67

while the Liquid are 1 step ( 2 coat) process apex coverage/cost per shower $70.00 2+ gallon maybe even less.
My recommendation is the pro red from C-Cure I had lots experiences of selling and using it myself.