I travel quite a lot and take out taxi is a very convenient service. When it works well it is great however I would recommend ordering over the phone.

They also have a website. When I ordered online and they forced me to save a login to place my order. It worked great the first time. Unfortunately I was staying in a hotel and every order I have placed since then has been sent to the original hotel and billed to my original credit card no matter what I enter on their website. Bizarrely the email confirmations they send match the what you enter online but what the dispatchers see on their screens matches whatever was entered for that first order. Beware if you are traveling on business or if you have moved!!! Be prepared for a 3-4 hour wait while they try and reconcile what you see on the website and email confirmation compared to the old information seen by the dispatchers.