KWA's are said to be the best because they're widely available in the US. On the other hand Tokyo Marui pistols aren't. They don't get imported into the US, and most people don't order from overseas (after all, they don't need to for anything else and things are cheap enough there to not warrant buying from abroad)
I'd say if you couldn't get a TM, KWA would be the next best option, but get a Marui and you won't regret it.