T-Mobile Offers 42Mbps 4G in 3 Cities Now. 25 by Mid-2011

I found this Mashable item republished by CNN quite interesting because of one sentence.
CNN: Why AT&T bought T-Mobile
Mashable: Why AT&T Bought T-Mobile
AT&T may be talking a lot about 4G in its press release, but T-Mobile has no LTE technology or infrastructure to offer.
This is interesting since T-Mobile USA has been claiming it has the largest 4G network. It is true that they do not use LTE technology (T-Mobile uses HSPA+). They also just turned on the ability to boost their 4G network to 42Mbps in three cities.
T-Mobile Makes America’s Largest 4G Network Even Faster by Lighting Up 42 Mbps Speed in Las Vegas, New York and Orlando
T-Mobile says that 25 markets will have this increased 42Mbps option by mid-2011. This seems like considerable “infrastructure” to me.