id go for the g&g range only hear good things at the moment about them. plus i wouldnt let any of those package deals sway you the batteries will probably be cheap rubbish same with the charger and tbh even if you buy the g&g you linked the price will be roughly the same after buying a half decent batt and basic charger as the m15a4s you linked.
src/jg do some decent g36s
ics/ca i dont know much about there sportline versions they make some decent higher end models though so would imagine they are a fairly safe bet