I really want the Mega Metagross Collection now.
As for Basic Metagross-EX, it is fairly weak. Magnetic Laser can move Energy off of something on your Bench that you powered up earlier, like a damaged Dialga-EX, but is otherwise too weak. Squared Attack is just plain awful. Rarely will it ever do 100, maybe 150 if you're lucky with Victini. Yea, Mega Metagross DOES have the Mega rule, but I feel that it still is really viable for anyone who wants to try it.
Substitute Robot is going to make Megas that don't have Spirit Links a lot more playable. Gatling Slug is really great, especially since you get that acceleration and consistency from Bronzong. 4 Metal Energy does 170. Even 130 for 4 Colorless Energy isn't that awful, since you can power it up with Blastoise or Emboar. I could definitely see Emboar/Pyroar/Metagross be a thing.
That said, though, since M Metagross-EX is a promo, I doubt it will see play in tournaments. Still, I plan on getting a Mega Metagross collection for Christmas, and then maybe use Gift Money or Trading to get my hands on a few more copies of the card, so I can get a 2-2 line at least for my Bronzong/Cobalion LTR Budget deck.
Hopefully the Booster Packs are weighed in our favor. Even if it is just about 2-3 holos total, that would be nice. Let's see, here is a value calculation of the box:
-Metagross-EX (est $4)
-M. Metagross-EX (est $6)
-8 packs (est $3.50 each, so total to $28)
-The Jumbo (est $5)
-The Playmat (not sure exactly, but probably about $6-8 depending on the material)
So, overall, this totals to 4 + 6 + 28 + 5 + 7 = $50
Again, just an estimate.