imho - for baby quilts, i like polyester, because baby quilts get washed a lot, and for that much washing, i think poly holds up better and dries faster.
for grownup quilts, i like 80/20 cotton/poly. when it's used with a topsheet, it doesn't need as much washing or drying, so it holds up longer. it has a nice drape, and it quilts well. it's very warm. cotton will pucker after washing and drying.
for wall hangings, it depends on the look you want. if you like the puckered look of antique quilts, then use cotton/poly and wash it after you're finished.
the cotton part will shrink up and pucker. if you want a puffy wallquilt, i would go with a puffy poly, so that the stitching really sinks in and shows. unless you hang it in the kitchen, it won't get washed as often as a bed quilt.
i would spend more on real usable quilts than on wall hangings or table toppers, etc. because i want it to hold up well after many washings.
table toppes are more for home decor and are not hard-used. in the end, it depends on the look and warmth and usability you want and can afford.
i use warm & natural cotton/poly. i make bed quilts. for babies, i always used to use poly.