Just thought I'd report back with my purchase, I bought the 3200mAh slim rounded white case branded "power bank"
takes around 6 to 8 hours to fully charge using the standard wall charger for my HOX, remains cool while charging which makes me think its not using 1A of charge but 500mA.
When fully charged it will charge my HOX from ~2% up to ~60% in around 3-4 hours. All up would be an addition of around 8-10 hours battery life
While charging both the case and phone get a bit warm, I'd say around 25-28 degrees(C), not hot but noticeable.
Case is surprisingly well built, no squeaks gaps or imperfections that I can see, aside from the "stand" this is really nice
Very happy with my purchase, bought for $31USD and shipped to New Zealand, took less than a week from Hong Kong
Hope this helps, the Mugen power batteries look good but far too much money for me, I wont be using the batteries daily so a reduced number of cycles is not an issue for me