I have no experience with the foreign branches, but considering how much emphasis is placed on customer service at TMobile USA, it's surprising how badly that was flubbed. TMobile USA pushes that they are competing to be the best service organization in the US. (Not best service of a cell phone provider, but best of any company. http://www.t-mobile.com/company/PressReleases_Article.aspx?a...
shows a bit of the push.) I'll also point out that verizon seems to have beat them in the last rankings.
I can't speak as to how well this works in practice at their actual facilities. I only went through the standard initialization after a takeover at a location that is scheduled to be closed soon. I've already found a job elsewhere, so no worries there.
For what it's worth, T-Mobile USA does pretty well in the Consumer Reports recommendations (worse than Verizon, better than AT&T and Sprint). I find it a little funny that another comment in this thread lauds Apple for focusing on every detail of the user experience, and yet Apple chose to partner exclusively with AT&T, which Consumer Reports describes as "Home of the iPhone but trails the better carriers in almost all respects."
At a different previous job, when AT&T and Cingular were merging and TMobile was the other big customer (company provided US GSM services), TMobile had the reputation of being the professional ones.
When the carrier I was talking about earlier was taken over, I saw a somewhat poorly organized IT merger, but nothing that detracted from that reputation. The original interactions were on the GSM network side, while the takeover occurred while I was in the application development/e-commerce side of the purchased company.
Consumer Reports agrees with my personal experience with each company, and as a customer of Verizon.
I can't speak as to how well this works in practice at their actual facilities. I only went through the standard initialization after a takeover at a location that is scheduled to be closed soon. I've already found a job elsewhere, so no worries there.