So, 52 ended up being a wonderful series in the end. I was low on it late in Act 1, but it grew into an explosive conclusion and overall really good series. Yes, the multiverse is back and I have no clue where they are going from here and I had hoped Countdown would excite me more than it has. I would dare say that 52 was the strongest of the big events that DC has seen over the past few years. I'd rate them this way (not including the current Countdown series):
2. Identity Crisis
3. Countdown to Infinite Crisis
4. Villains United
5. Infinite Crisis
6. The OMAC Project
7. Day of Vengeance
8. Rann-Thanagar War
9. World War III (4 issues expanding upon 52 #50)
Now we have Countdown and I think I am seeing a vast difference between an arguably All-Star creative team (Geoff Johns, Mark Waid, Grant Morrisson, Greg Rucka, Keith Giffen and Steve Wacker/Michael Siglain) and a Countdown's rotating set of creativity (Paul Dini and Keith Giffen being mainstays with rotating writers).
I think Countdown's biggest strike against is the fact it is happening in continuity with the current DC universe, unlike 52 which told the story of the missing year. With it being in continuity that means there will be crossovers if you want to read more about what is happening. Marvel did a pretty good job with crossovers while Civil War was going on by keeping the main story in the main book while letting people read more of the story elsewhere. I don't have the same sort of faith in DC to be able to keep the reins held on this crossover. So far we've seen connections to events that started months ago and just this week at the end of #47 we see the Amazon's attacking, something that started in Wonder Woman weeks ago. If they aren't careful it is almost assured that a comic could spill the beans about what happens in Countdown or what happens in another book that affects Countdown.
So far I am not as impressed with Countdown as I was with 52, but I shall continue to read it. If you want my honest opinion though I think Marvel has better editorial control over their books than DC seems to have. Marvel is running on all cylinders at the moment with some excellent new books out there (Avengers: The Initiative, The Mighty Avengers, Omega Flight, Nova, and New Warriors just to name some) that tie well into the aftermath of Civil War and will soon tie into World War Hulk and whatever the upcoming X-Men event is.
In the end though it may be interesting to see exactly what DC is counting down to with the series. Are they going to reboot the whole universe again? I hope not, but who knows at this point.