Monkeyman- 75/25 is a rough estimate by me. Ill explain in detail why I think the odds are that way...
Gardevoir/Gardevoir EX has three ways to deal with threats. Gardevoirs attack, and both of Gardevoir EXs.
Gardevoir's attack is strong for one energy. Unfortunately, it is virtually ineffective vs this deck. Ninetales discards all NRG, so it deals damage equal to the # of NRG on Gardevoir. Seeing how any Gardevoir with that much NRG would be the target of Ninetales attack in the first place, I do not see Ninetales losing to Gardevoir. Blaziken, if done properly has 2 NRG left after using its attack, and KOs Gardevoir in 2 hits anyways, excluding healing. Gardevoir has major issues dealing enough damage to kill a single Blaziken unless its uber-pumped. Even if it is it will not take down more than one Blaziken, and usually in order to get the Gard strong enough to fight, you are forced to neglect any other energy drops on other Pokemon.
So while yes, Normal Gardevoir can work effectively, it is not great at fighting such power, especially not when they end their turn with low NRG counts.
Gardevoir EX is a bit more trouble, but it can be played around. First of all, it yields 2 prizes which is just beautiful for this deck. 6 NRG to KO is easily obtained on a Ninetales as well. The key with dealing with Gardevoir EX is not to overload your NRG count.
Gardevoir EX's first attack can be brutal. You need to know not to get too large of hand. If you can effectively control this, Gardevoir than needs to resort to its most devastating attack, its second. This hurts heavily as the more NRG they get in play they deal heavy damage, as well as dealing damage for all of your NRG in play. Seeing how quickly this deck gets NRg attached, that can hurt. They key is to simply get a Ninetales with 6 NRG out ASAP. Dont power much else until you have this guy ready. A normal Gardevoir cannot threaten you much if your active has no NRG. That means they need to use a EX to attack, and even if you end up sacrificing a prize to it, your making it up by taking 2 and killing alot of buildup, and while you lose all your NRG, you have Blaziken to rebuild every turn. They have Gardevoirs PP, but it is much less effective, and they take damage for using it. They also have a finite number of NRG to do it with.
Gardevoir EX/ Gardevoir is one of the best decks in thsi format, if not the best, simply because of how versitile it is, and how its only weakness is itself and therefore its main weakness is mirror match, so its 50-50. That makes it incredibly hard to counter. I do believe Blaziken beats it more often than not, especially in the hands of a plaer who knows how to fight it. Unfortunately, Blaziken DOES have an exploitable weakness in Water to keep it in check.
Anyways, onto the lists given by Monkeyman, I used to run Magmar EX in the list. Its not that good. For 3 NRG, Id much rather use Blaziken. Yes, its an evo and doesnt have smokescreen, I know. Unfortunately, the 2 prizes given up by it does hurt its appeal. This deck is very effective as it does not need to use any EX pokemon, and hurts those that do because it can OHKO anything. You end upe ffectively needing to kill less Pokemon with the same ease. Ninetales is, IMO required here, as while yes, running Magmar may make it less vulnerable in the opening game, I would rather sac a prize to get set up. The resulting strength you gain mid and late game, and against your weaknesses by running Ninetales instead is too great to pass up.
Switch, psycodad, is actually used for multiple reasons. Besides the occasional close game where you really need to hold onto your NRG, it is used for the following reasons. First, you need a way around status effects. Yes, most status is grass, but it can still be very useful to have a way out in case. Secondly, and the main reason, lets say you have a Ninetales out. It has 0 NRG. Retreat for 1 fire. Use 3 Blazikens, attach to Tales and use Switch and hit for 9. There are alot of times that you want to get a guy to the bench to get extra NRG on it and bring it back active, and that cannot be done when you can only retreat once. Plus due to Delcatty oracle, you can fetch both them and Hyper Potions as needed throughout the game.
Monkey again- You mentioned the better attack Blaziken...I am highly considering going 3-1...2-2 is not good enough ata ll. You need at least 3. The tecH 110 HP one also spites AQ Suicune, who may see some tecH play,e specially in Sceptile. It not only OHKOs Suicune, but can live even its best hit. I wish one was an EX -_- lol. Oh well. But yeah...I figure I gave some thourough details to the deck here...lol.