[joefourier]

It depends on the country and city - here in Ireland the taxis are almost always a class act. My local taxi company allows payment via smartphone and even sends you the invoice via SMS or email if you need it as a business expense. I've even had a driver turn off the metre and show me around once he realised I was new to the city.

And tipping, although appreciated, is not at all mandatory like in the states.

[mseidl]

German taxis are great.

[chrisseaton]

In my experience they get evasive and rude when you try to pay with a card.