I was drawn to T-Mobile to save mobile-to-mobile charges as my partner also has a T-Mobile phone on contract. I also liked the opportunity to pipe calls through the Orange network at no additional charge should the T-Mobile service be unavailable.
Well, everything was going just great... until I tried to configure my Email client with my Gmail acccount, then another, and another. I tried authenticated POP/SMTP, then IMAP/SMTP, various ports and security settings, and have given up.
Suffice to say that there have been countless users for years with problems setting up reliable Email connectivity with Android phones on T-Mobile, and apparently T-Mobile features alongside the worst of the bunch for Email reliability via the mobile phone network. Very occasionally I can send Emails OK but mostly not, and in this age of mobile connectivity the ability to send Emails with reasonable relability is a minimum requirement.
For the more technical enquirers, simply Google: discussions Problems sending email on port 587 ...and review the timelines as I can verify these problems persist.
In all fairness, T-Mobile are not the only problem providers regarding Emails, but worthwhile doing your homework if sending Emails on the move are an important part of your daily life.
If you have good eyesight and able to use webmail and teeny buttons via browser on your mobile phone, or are connected to WiFi, it's OK as you might expect, but if you want a reasonable chance of sending Emails via your mobile Email client when on the move then don't waste your time and 1p on this SIM.
Such a pity as the overall phone and broadband coverage is very good.