{simplegrade:5}
I really can't say enough good things about this U.S. based retailer. Not only because of their direct support of this website, but their direct support of U.S. based airsoft in general. Airsoft is not a commodity for sale for AEX, they truly have passion for the hobby/sport with a huge emphasis on quality.
In the past, AEX has stopped selling certain airsoft manufacturers products, due solely to poor quality. They continue to sell the highest quality airsoft products and stand firmly behind all the products they sell with a 45 day warranty. AEX is always well stocked with high end airsoft products and their technical staff is extremely knowledgeable and helpful.
AEX sponsors most major airsoft events/websites/publications and is one of the oldest U.S. based airsoft retailers.
AEX has 5 retail locations in CA, and a most triumphant website for your shopping pleasure.
Orig Review 2002
I have purchased many airsoft guns and accessories from Hong Kong and locally here in California. I have been very fortunate to have met an dealt with some great people and purchased some great airsoft products and services. In most cases Japan will not ship airsoft directly to the U.S. and precautions have to be made for Hong Kong retailers to sell to the U.S. because of U.S. Gun Control Laws and Manufacturer Copyrights.
Airsoft Extreme
Location: California, USA
I have purchased my first AEG from Airsoft Extreme and many accessories:
Marui FN P90 
This was my first AEG, and the guys at Airsoft Extreme were very patient and informative for me the first time buyer. I have added an P90 Silencer, East Sling. Other then that it\'s stock and VERY accurate and reliable. The red dot scope works well too unless your are wearing a full face mask during skirmishes but puts you right on target.
Currently this is how the rig looks like 
Airsoft Extreme is a reliable, ultra honest, U.S. Based airsoft retailer. The are one of the oldest U.S. Based airsoft retailers and now have 5 retail locations; Santa Clara, CA; Los Angeles, CA; Oakland, CA; Sacramento, CA; San Diego, CA.
My friend purchased my first AEG for me back in 2002. The original TM P90 and it has been working like new since it was first purchased. Back then the guys were very patient with all of my questions and mind changing that you normally see with a first time AEG purchaser.
A few months later I purchased a TM M4 R.I.S. from a Hong Kong based retailer called Redwolf (RW has no business relation with AEX). This M4 R.I.S. broke soon after I received it and even though Redwolf has a U.S. based retailer that was willing to look at the M4 called the Qproject, I sent my broken M4 to AEX, since I remembered their high level of customer service. I had AEX install a Systema Metal Body and M-120 spring and Gear Upgrade. I wanted to have them to also install a bunch of other upgrades (i.e. Metal Outer Barrel, Reinforced Gearbox, Etc). They honestly answered that I didn't "need" anything else. This shocked me, but I really appreciated their honesty. I have since used AEX for all airsoft repairs and complicated upgrades.
The down side is being a US based airsoft retailer, is the customer pays more then if purchased directly from a Hong Kong retailer. But you don't have to worry about customs seizing you gun and it's comforting to know AEX stands behind everything they sell which is not the type of service you receive from an overseas purchase.
Their email replies are prompt and pleasant and both pre and post service communication are good. AEX also offers many Custom Rigs with some interesting variants. They also offer a starter packages on most AEGs.