I assume by now anyone who is interested has had a chance to read the 'Big FAQ' recently released by GW for 40k. Most have probably formed opinions already. Some think the changes are not enough, others think they have gone too far. The Beta 'deep strike' rules in particular seem controversial and have many people cursing GW for ruining everything forever. My initial instinct is to ignore the beta rule for now, as it will quite dramatically change the way I build my Tyranid lists.
Turn one and half the army turns up from the skies/underground, protecting them from fire and immediately piling on the pressure. I can see how this may feel overwhelming for an opponent and a bit like a 'cheap' tactic, but in my experience I very rarely got a charge off or any significant damage from my reserves on the turn they came in. It didn't feel broken. However thinking about it, aside from the Mawloc right in the midst of the foe, there isn't much I couldn't have replicated by starting these units on the board. In fact I'm pretty sure the Gargoyles would have been closer. I've been moving away from the Genestealers in tunnels tactic as an offensive one, and instead just as a psychological blow, but if I were to march them their full move up the board, I've seen that have a similar effect.
I guess what I'm trying to say is that I'm not convinced by the Beta rules, though I think I agree with most of the rest of the FAQ, but if they come to pass, they are not the end of the world and I'll adapt. In the meantime it might be best for us all to actually play some games with the rules and see how well/badly it goes. That's the whole point of 'beta' rules - they might be rubbish but the only way to know for sure is if people play them and give their feedback. Just don't knee-jerk reject the rule, or blindly accept it as a given.