A matte, true white panel will have the same effect photographically, regardless of the material. The differences are portability (compactness, storage convenience) and price. I like to carry mine around in my car, not having to worry about creasing, bending or denting them, so I use collapsible fabric panels of various sizes (white or black mostly) which have a spring metal outer edge. They quickly fold into very small bags and pop back into shape when needed.
I also carry lightweight light stands, mini-booms, reflector clams and counterweights to hold these reflectors.
I have (2) 36" 5 in 1 Collapsible round reflectors. (White, Black, Gold, Silver, and Translucent white.) They fold into a nice small 10" or so zipper case which can easily be attached to my camera bag.
Nikon D700 l Nikkor 28-70 f2.8 l Nikkor 18-35 f3.5-4.5 l Nikkor 50 f1.8 l Sigma 70-200 f2.8 l
(3x) SB900's & SU800 l Manfrotto Tripod and Head