I've tried both the Meltonian Water & Stain protector and the Apple Garde Rain & Stain Repellent. My observation:
They both have a strong chemical scent when you spray them on the exterior of the bags ( tried them on all my BVs, nappa and the goat skin specchio ). No remarkable change on the leather. Though I'm not brave enough to try and do any water testing. I was more concerned if it will darken the leather, it did not.
Interior - Apple Garde, the suede interior of the bag slightly darkened.
- Meltonian, no change.
Exterior - Apple Garde, the leather glistened with the spray after application. Left to stand for 12 hrs., i buffed with a buffing cloth. Looks same as before application.
- Meltonian, the leather appeared to have a slight whitish film after spray application but after 12 hrs. and buffing this also disappeared. Looks same as before application.
Test Subject: for Meltonian - Intrecciato Tote, Copper East West Belly, Veneta Ash Scuro
for Apple Garde - Large Campana Ebano, Balenciaga City 09/ Part Time 09
HTH!