I guess it depends on who you ask, but living in Japan I got the impression they're seen as an important role in society. Every taxi I had ever taken had a middle aged man in a business suit driving. I'm not talking about "getting picked up from the airport on business" taxi drivers, I received extremely professional service any time of night from any random street. Others in this thread point out that they're sometimes crabby, but as long as you know the basics of Japanese etiquette I think you're in for a good experience. While a was cautious at first (as any person in a foreign country ought to be), I quickly stopped feeling like I needed to protect myself from scams.