I paid something like 85 as it was on sale at the time so it was definitely well worth it at the current price after click to use the coupon thats listed on the listing its still worth it. I can charge my phone 4500mah battery from dead 4 times so how much power does one need as long as you recharge it when its got less then what you consider useful to you it will charge as fast as the charger you plus it into will allow i dont have anything that puts out 140w so i charge it at 120w. It charges in about the same amount of time my phone does which is 1 to 1.5 hours. It takes 2-3 hours at 60w or less. So know what the output is that your charging it with as the amount of time varies quite a bit when you drop down that far
