If it is going to kids, they like the puffiness that you get with poly batting. If it is going to the elderly, the lighter weight works for them. If it is going to a hospital, I would check, they may want cotton that will wash better in hot water.

I especially like polyester batting for quilts that are going to "see a lot of action", particularly washing, or if I don't know who will get the quilt. It's a little harder to machine quilt -- I did a lot more pinning than I do with cotton -- but it washes up great and is very warm. I like my charity quilts to be warm and sturdy.

I use either the polyester batting or fleece for all my quilts. So far no complaints. I have discovered that for most things the fleece is my preference as it doesn't shift like the fluffy stuff may. I've also used the "snow cover" (designed for decorating with the village houses) as batting for table runners or placemats. Got a bunch of it on clearance a few years ago.

A lot depends on the specific charity.

Charities that give quilts to children in the hospital typically request cotton batting (or 80/20) because it holds up to the harsh hot water washing and drying of the hospital laundry, especially since the quilts of some children need to be washed every single day.

Charities that send quilts overseas often request polyester batting because it dries much faster than cotton or wool -- helpful for countries where families and hospitals do not have dryers.

LOve the little bit of puff. I use cotton, poly...whatever I guess I am not a purist.

Cotton batting needs to be quilted pretty close together or it will shred and pill in wads after lots of use and washing. I don't like it at all! If you buy good quality fleece I think that would be fine to use as batting, but some of the thin cheap stuff is really stretchy, however some people use minky and I think that would be horrid as it stretches if you look at it.

Poly is a LOT less expensive and it holds up wash after wash just fine. It's warm, it's comfy, and it's a little fluffier. Sometimes I like it better than cotton. If you have problems with shifting (I never have), just use a lot more pins or spray basting if you prefer. I think that if it didn't work well, there wouldn't be so many types available on the shelves and manufacturers wouldn't keep making it.

I have not used it but have wondered the same thing. I love cotton or 80/20

It depends upon the type/brand of cotton batting. Warm & Natural has a scrim, which holds the cotton together. It starts out a bit stiff but softens with each wash. It's also one of the easiest to machine quilt, IMO.

Poluester batting?
 

I have used poly batting for many years, hand and long arm quilting for family and QOV (Over 150) with no problems of shifting, wrinkles or any other problems. I will not use any other batting unless doing a quilt for a friend who furnishes other batting. My quilts are washed a lot--for babies up thru weddings.
Phyllis in Oregon
72 yrs quilting