Speculation: Here there be spoilers & a deck list!

Ok, so I love set previews.  This is my favorite time in Magic, just before a new set comes out and I get to imagine the possibilities.  Now, I've been known to live in Magical Christmas land when I'm thinking about thses cards, and I've been WAY off in the past.  Of course, that's half the fun!
So let's dive into Mirrodin Beseiged!

Btw Thanks to MTGSalvation for the spoiler!

Signal Pest
Artifact Creature - Pest
Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.) Signal Pest can't be blocked except by creatures with flying or reach.

I so hope this guy is real.
A 1 drop lord for every token strategy ever conceived with a double for tempered steel decks in that it's an artifact.
One of these, plus memnite or ornithopter seems good.  Add to the mix how easily the robots deck dumps its hand onto the board and you have a recipe for some scarily fast kills.  We're talking turn 3, turn 4 reliably.
Let me give you an example:
Turn 1 - Memnite, play land (Darkslick Shores), Signal Pest, mox opal, memnite.
That's 4 damage attacking turn 2, that could easily be 10 with a turn two dropped tempered steel.  Even without another land this hand is pretty crazy, and it's standard legal. Have I mentioned that it adds to the number of hard to block creatures in the deck as the flying/reach clause is quite relevant.
Best part about this guy is that he's colorless.  He goes into EVERYTHING.  Goblins? Check.  GWb tokens? Check. Elves Aggro? Check.  For every deck that wants to go wide instead of big, this guy is the nuts.

Another possible addition to the robots deck that might give it some staying power instead of being the 1 hit wonder of fast aggro or bust is this:

In the example I described above, I could play this turn 3 if they aren't dead already, and then they will be next turn when Mr Evil Tezzeret goes ultimate on your face for about 12 drained.  Seriously this card makes your ornithopters into 5/5 flying dragons PERMANENTLY!  Free dragons?  Yes please.  Not to mention Memnites, Signal Pest, or Steel Overseer.  Definitely adds staying power to a deck that was really good at stalling out once the opponent stabilized.  It also works in the same spot that ranger of eos worked in the worlds robots deck in extended.  He refills your hand, with some card selection.  While he is not quite as noticeably strong as the ranger, has a lot of synergy, and again standard legal.
I suspect standard robots will look something like this:
Rogue Insight's MBS Legal Robots
4 marsh flats
4 seachrome coast
4 darkslick shores
4 plains
2 swamp
4 Inkmoth Nexus
4 memnite
4 ornithopter
4 steel overseer
4 signal pest
2 Shimmer Myr (flash for all my creatures? YES please!
2 Etched Oracle
3 Tezzeret, Agent of Bolas
4 phyrexian revoker (this guy is SO good)
4 Tempered Steel
2 Dispense Justice (or Doom Blade or Go For The Throat depending on the meta) (In retrospect I think that Inquisition of Kozilek or Duress would be better here than removal, but again meta dependent)
3 mox opal
2 Molten tail masticore

3 lords, some reach, a number of ways to avoid your opponents traps, disruption, seems resilient.

What happens when Tezzeret makes a Blinkmoth into a 5/5 infect?  I don't know, but I want to find out! Is it no longer an artifact at end of turn?  Does it reanimate as a 5/5? I think the answers are yes, and no respectively, but I'm not sure.  Any judges out there who can answer that one?

Some others in here that I hadn't talked about yet:

Love this guy.  Pithing Needle on a stick.  Notice that it hits mana abilities.  Noble Heirarch? Shut Down.  Jace, TMS or otherwise? No Brainstorming for you. Oh and he's going to be a 4/3 for 2 a LOT of the time.  But again this is a card that goes into every deck.  U/W? Check.  U/B? Check. Valakut? Check.  Being an artifact really means that this guys is versatile as hell.  The new swiss army knife of the format, and he's searchable by fauna shaman and he turns off fauna shaman as well.

What about this little number:

Now some of you are saying, this?  Really?  It's a +1/+1 equipment.  Not much to get excited about.  Normally I'd say that was true, but think of this as Modular from the original Mirrodin and you have a better idea for how this card will just consistently and beneficially affecting limited board states (maybe constructed, but I doubt it).  It's an equipment I don't feel bad casting when I have no creatures because IT'S a CREATURE TOO!  Imagine bouncing it with glimmerpoint stag, and oh look I have another creature.  Not bad at all.  This is a turn 1 play I expect to be seeing a lot of for the next few months.

I know everyone is bonkers on twitter and abroad about this one so here's my spin:

I know it's good.  But it's not the end of the world.  The sky is not falling, Chicken Little.  There is nothing to see here, move along.
Yes it can be cheated into play.  Yes it's effectively a 1 hit kill.  Yes it has trample, and yes it's indestructible.  No it's not unbeatable.  Exile removes it, which is a lot in the format right now.  Arrest hits this just as easily as it does a wurmcoil engine.  I really don't see what the big deal is.  Even a lowly tumble magnet makes this thing irrelevant long enough to find an answer.  Not to mention infect shrinks him just like it does every other indestructible in the format.
He's good.  He's the new go to guy for Polymorph (although I think there is still an argument for Emrakul), and I definitely think he's a card to watch, but he's not broken.

Ok, I have a lot more to say, but that's all I really have time for tonight.  I'll be back more this week for more speculation.