Open or closed?
There have been few if any truly open Linux smartphones (there is Openmoko but that's neither HSPDA nor 3G). The manufacturers seek to lock them down to a greater or lesser extent.
In some cases the applications which can be run are restricted.
Often recompiling the OS is obfuscated or made near impossible. For example they might modify the kernel and then post no, incomplete or just plain inaccurate patches (in violation of GPL but they don't care).
Binary only proprietary device drivers and NDAed to hell and back hardware specs are also common. There are many existing handsets that can be reflashed to run Linux to a greater or lesser extent but lack of hardware specs for critical components make this very difficult.
This may be partly because Linux doesn't fit well with the business model of some mobile phone operators: "if you want the bugs fixing or the latest OS version buy another phone".
It will be interesting to see if this effort is yet another "closed Linux" or truly open this time.