I've found small plastic bits stuck to virgin Costco towels out of the package. Recommend inspecting them or washing them at least once before using on paint.
If you can get it in writing that they will fix any exterior defect (dents included) under warranty that sounds like a deal to me. Although if something sounds too good to be true...
You can't go wrong with either. Ech2O probably boosts the protection better but Uber is less prone to streaking and cheaper because of the dilution ratio.
Good place to start
Favorite Microfiber for Specific Detailing Task List (Autopian Suggestions)
http://www.autopia.org/forums/car-detailing/186913-favorite-microfiber-specific-detailing-task-list-autopian-suggestions.html