None are really better, they are the same brand. Lancer Tactical has very cheap and low quality externals, if you want an M4 styled gun look at JG and if you want an AK, look at CYMA. Those are much higher quality and are just as good performance wise.
Here's a CYMA on sale right now, full metal as well! http://www.evike.com/products/32773/
And a JG M4, same style: http://www.evike.com/products/29843/
I also recommend a LiPo battery, they can be had for about $8-10 on HobbyKing, but you need to take a little more care of them (store them in a LiPo bag, those are about $3 on HobbyKing, and use a LiPo charger).
LiPo bag: https://hobbyking.com/en_us/lipoly-charge-bag-14-x-23-cm.html
Any LiPo charger should be good, but make sure you get the balance board and you have the adapters for Mini Tamiya connectors.