According to the post, the workaround will push email headers (subject/time/sender etc) but not the message body. That will be retrieved 'seamlessly' when you open the message - in the same way that BlackBerry today only downloads anything after the first 2K of the message when you scroll past the More marker.
Faster networks will make the pause while the message arrives much shorter; the new 8700g will be pretty speedy on Orange's new EDGE network, though not as fast as the Palm 700w on the US EVDO network (personal prediction here; perhaps a 3G Palm 700w for the UK in the second half of this year when the 3G radios eat less battery).
But it means you have to be in coverage to read your email - as opposed to looking at the message and thinking 'wow, I need to read that; shame I'm on the tube for the next 45 minutes with plenty of time to read and reply but no network connection'. If I have time to stop and retrieve email in coverage, it's not going to be any faster than stopping and hitting Send/Receive on a Windows Mobile device like the MDA Vario (where I get excellent predictive dialling and over the air synchronisation of my contacts and calendar without needing the BES server).
You just can't assume universal connectivity; that's the failing of many mobile systems. You need to handle offline and online smartly and seamlessly. The asynchronous 'it's just there' of BlackBerry is the secret sauce; that's why it's so much better a push email solution than anything else I've tried yet. Make me get involved, demand I push the right button at the right time and you've taken away much of the value. I find I'm hoping the NTP patents fail and the BlackBerry stays the same; and I do hope any changes don't happen during March when I'll be in the US, relying on my BlackBerry for email and blogging in motion.