As with everything iPad, the Smart Folio has lovers, haters, and those who feel a mix, depending on expectations and varied uses. I suggest buying from source with a free return policy.
If by “folded” you mean when the front cover is flat on the back, the two panels stay put. If you meant folded into a triangle to prop the iPad up, I fall into the group that finds that too unstable for regular use.
When lounging, I tend to prop the iPads on a pillow, furniture, or my leg, and a bare iPad is simply too slippery for me, so the Folio provides enough grip and sufficient protection when storing them around the house, even though I personally find the Folio’s edges to be a bit too sharp (that love/hate thing).