What is the best cab app to use these days in London?
Just get a black cab and appreciate their knowledge. http://www.theknowledgetaxi.co.uk
or take your chances and go with an unknowledgeable Uber driver.
BTW the proper way to hail a cab in London is:
http://www.bloomsbury-international.com/blog/2013/06/07/british-culture-how-to-hail-a-black-cab-taxi-in-london/
Different part of the world. Embrace and respect the difference.
I've used the Green Tomato app in London and have had good experiences. It's like Uber...just another company.
Always use a black cab, they are safe and more knowledgeable then the other cabs. It is a long hard process to become a black cab driver.
I like HAILO. We had a weird mix up where another party hopped in our cab and then a second one arrived to pick us up, but since he did not have our "order" he had to charge us cash. The fare for the cab that was supposed to be ours was charged to us, but within 24 hours of sending them an email, HAILO sorted it out and refunded us. The cab drivers are always so nice and efficient! But we only use cabs for short haul, certainly not to the airport.