I've been using this mod for over six months (one 9 months). I was so impressed with the first one I bought at Canvape I purchased another without hesitation. Battery life is impressive with the 5000 mah charge. Lasting at least 12 hrs continual use with the temp controlled 0.15 ohm coil (40 watts), and much longer with 1.5 ohm at 20 watts.
2 amp charger recharges unit in about 4 or 5 hours safely. 1 amp chargers take about 9 hours to fully recharge (overnight).
I'd recommend downloading the manual from Eleaf (free of course). It is very important as it has a lot of features which you will want to know about in order to properly use the device.
Only negative I have is one of the devices occasionly mis-reads the ohmage of the coil, setting it to 0 ohms. It is a quick fix though with only a few buttons to push.
I expect to buy more though at 9 months I have not seen any degradation in charging capacity.