My experience is...
Squadron you can count on relatively quick and correct, but they might be slightly more expensive than some.
Tower Hobbies has good stock and great pricing but their packaging leaves something to be desired, I had a Attack Radio, Battery and Multi-charger all whipping around in a big box with one deflated air-pack. Another shipment had a few dented or crushed boxes from the same problem. So far no damage to the actual mechandise.
Hometown Hobbies will get you anything out there and have the probably the best prices overall, but you usually have to wait. They don't ship for 6-8 bus days from order normally but might be longer if they have trouble finding things.
Hobbyworks has some incredible specials, but it's hit or miss if you are looking from specifics. They don't list a lot on their site, but are very cooperative.
By the way, has anyone noticed Tamiya paint lids are always loose?