Bought size 44 thinking it would fit like the Flexile and Ortholite insoles, which I swapped seamlessly between the Mudee and Pace). The Rebound insole is too long for either of those, as well as the Citee I just bought. The tip at the big toe seems to be the culprit, as it is disproportionately long compared to the 5th toe compared to the Ortholite insole. Without trimming it fit perfectly into a size 45 Reebok Nano with a more conventional toe box. Trimming ~6 mm or so from the tip of the big toe spot allows it to fit into most of my size 44 shoes, Freet or otherwise. The narrower midfoot allows it to fit into a variety of lasts, compared to the Ortholite which has a straighter cut; I think this is a good thing but I could see it not fitting so securely in some shoes, or causing blistering on some medial arches depending on the shoe.
It seems to be holding up well and providing just enough impact protection and sensation of energy return. I don't expect it to compress and feel dead as soon as a PU or EVA insole would. I've waited years for a zero drop, wide toe box ETPU insole so this is a game changer. If/when I buy another set I will go one size down.