I use them, they work well, aside from the Mickey Mouse battery system. Has its own battery pack, and charger. One of those plug it in and leave for no longer than "X" hours or if the battery is hot, it is charged setups. A proper charger system would be great so you could know whe it's charged, or even how much it's charged. Luckily I have rc cars and use the decent chargers from that stuff to look after the led battery pack better.
That's my only complaint with the set up