I purchased a tecknet in 2014 and rav power in 2017 from Amazon and both are still going strong. The model numbers are discontinued such is the pace of change but I would buy both brands again. I prefer the tecknet because it has a proper on/off button where the rav power does not
After some testing and comparison, I've decided to get Villain power bank few months ago, when there was a discount on them. I thought that discount can be as a sign of bad quality, but I was wrong, it works perfectly, and it's 20000 mAh - last for 5 days of travelling.