Sony's options were to:
Release a crippled product with only half an EPG, by far the worst of any company that's had a go at this, or
Not release it here at all, or
(more realistically) integrate the official MHEG5 EPG into their product.
Going with the official MHEG5 EPG would have made it work and it would have allowed for series link support etc. However it would have stuffed the way the PlayTV EPG worked, losing features like a keyword search etc and the whole graphical display of PlayTV. It also would have been a major one off development that someone, Sony NZ probably, would have had to pay for. Despite what we think, we're just not that big a market here in NZ. Ironically though, the PlayTV literature in the UK says that it has built in MHEG5 support, so I had initially hoped something would have come with that.
Currently it's buyer beware. It's also a single tuner unit as far as recording goes. The hardware has twin tuners, but one is dedicated for watching only, and the other for recording only, so you can't record two different shows at prime time etc which is a point worth remembering. If it suits your needs though, then at least you can buy it here now.