Get the latest Macbook Pro and all the machines you have ever owned (including the T420) will look like buying form Toysrus.
MBP was one of my considerations but have ruled it out because of its price (for the same configuration with T series). Also I have a MB (quite old model) and my desktop is an iMac, so I don't really need another apple product line... so far very happy with my new toy and is playing around setting up ubuntu on it...