In my opinion I'd say KWA. They are about as solid if not more so than any other M4 AEG on the market to date. All the internals are perfectly matched to one another so there are no issues.
The biggest upside to KWA is that they listen to their customers about improvements that they would like to see, as well as flaws that are found with the product. I've had my KWA since November and would not trade it for all the CA's on the market.
As for the Li-Po ready claims it's because of the reinforced gearbox, the 8mm steel ball bearing bushings as well as the perfectly matched internals that make it capable of handling the awesome power of the Li-Po's straight out of the box. I run a Socom gear 11.1V Li-Po and have yet to have any problems after about 6000 rounds through it.
Yes they have some downsides. The hop-up isn't the easiest to change out with an aftermarket one as it's a two piece unit. The trades on the side are kind of a downer.
In the end it's a personal choice on which one to choose. You are going to find alot of differing opinions on what one is better and this is just one mans opinion of the topic.
Last edited by Sully; May 10th, 2009 at 02:03..