Pokemon-ex is easier to get it compared to Pokemon * because every booster box contains 3 to 4 pokemon-ex whereas every 3 to 4 booster box only contains a pokemon *...
Which to booster box to buy?
I'm also thinking which booster box to buy but after hearing some opinions, I've decided to buy EX Power Keepers. Anyway, lets analyse every edition that is going to be in the New Format after Worlds 2007...
EX Holon Phantom:Most of the cards in this edition are useless except for some like Holon Castform and/or Rare Candy & this edition has average 3 ex's which can useful if you know how to utilize them. Otherwise, this edition is not good at all. So if you think you need a lot of cards from this edition, then you should buy this, if not don't buy it...
EX Crystal Guardian:This edition has quite a number of useful cards. For example, Banette(Bandoom deck), Charizard δ(Charigross), Celio's Network(Important in all decks), Delcatty ex(Inferncatty deck). Overall, this edition is quite ok. So if you think you need a large amount of cards, the you should buy this.
EX Dragon Frontiers:Among all the EX editions, this my favorite edition
.This edition has a lot of delta pokemon besides EX Delta Species but I think this edition has better delta pokemon than EX Delta Species. This editions has a lot of useful pokemon like Feraligatr δ, Xatu δ, Nidoqueen δ & vice versa. About the trainers, this editions has some of the trainers reprinted from EX Delta Species & the editions before it, for example, Holon Mentor and PETM. If not these cards were not reprinted, every deck will have trouble getting out their pokemon in the next format. Now, about the ex's, every pokemon-ex in this edition are very useful. IMO, the most useful ex in this edition is Flygon ex δ. There's no useless pokemon-ex in this edition. You might think Kingdra ex δ is weak & useless, but it's not. Its just that Kingdra ex is not as good as the other ex's. So I strongly suggest you to but this edition if you want to get these powerful ex's...
EX Power Keepers:IMO, this edition has its "special ability". The rares in here are quite good, for example Delcatty(Inferncatty deck), Machamp(MARIO deck), Magneton & vice versa. This edition has more reprinted cards compared to EX Dragon Frontiers. About the ex's, the ex's in here can be useful if you know how to utilize them, for example, you may think Flygon ex is useless because of the attack but it's actually not IF you know how to use it & combo it with the right card. So, overall, I think this edition is quite ok also, so you can go ahead buy this if you want...
Diamond & Pearl:If you intend to use cards from DP, then I suggest you to buy this one. If you want to play a mixed deck, then try to buy DP boosters instead & buy other edition's booster box so that you can get other cards from other editions. Try to avoid playing all DP trainers in your deck because not all the trainers in DP are good, so you will need other trainers from other editions. In conclusion, I think you should not buy this edition because
refer to line 2 & 3 but if you want buy it, then go ahead...
P.S. All the analysis is above is just my opinion, so if you want follow it, it's up to you & maybe other members will have better analysis than mine. Anyway Good Luck in getting good cards...