The big problem with Cyber Sub's X-ray combos is that he hardly gets anything for it. Consider that his midscreen BnB is 40% without a jump-in punch (43% with), and 50% really doesn't seem like it's worth the meter. He can also get a no-meter 47% combo in the corner, where the best I've seen from a practical X-ray combo is 54%. The only time I suggest using his X-ray in combos is if you really need to close out a match or you really need the unbreakable damage.
Also, using breakers has nothing to do with defense. No matter what, your opponent is going to get some damage worth breaking in a hard matchup, and on top of that, Cyber Subs really isn't strong on the defense. He can control space by alternating bombs/ice balls/dive kicks, but he can't really "zone" so much as just get you off your spot with it. He's every bit as aggressive as Cage or Kung Lao, he's just more reliant on space control than they are. If you play more defensively, Sub Zero is probably a better fit for you.
33 ex freeze is a must
bomb traps are a must
I never ever use his ex slide, ex teleport, or ex dive.
thats just how i play with him. nothing sexier than throwing ex bombs, opponent jumps out and you jk, dive kick into a bomb freeze into combo.
Also while in the corner on wakeup ill do ex parry on wakeup to pit my opponent in the corner for a 48% combo punish
Pig knows what the fuck is up. Here I thought I was the only one who used 3 3 EX freeze. One question though: How do you get 48% off an EX parry in the corner? I can rack up 47% on my corner combo, but that's by comboing off jump in punch 2 1 freeze.
Personally, I save most of my meter for the EX divekick, just because it's easily accessible and really hurts. Cyber Subs has the privilege of being a character who has a lot of useful EX attacks without being anywhere near meter-dependent. Where some characters are dead in the water without proper meter use, it doesn't really hurt Cyber Sub's game if he doesn't have access to EX moves. This also means that you can spend more meter on breakers if you like to play more cautiously.
To give my breakdown of what to use where and why:
EX divekick fucking hurts. That's really the only reason to use it, but it's definitely reason enough. It can be a guaranteed punish with a the proper setup, and at 18%, it's nothing to laugh at. I find most of my meter goes here.
- EX parry is a great way to get out of pressure and get a full combo punish while you're at it, but it's risky. Generally, you'll only want to use this if you've been using your parry sparingly. If you start to abuse it and your opponent keeps running into it, he's going to learn to respect it, and so he'll try to bait it out or resort to moves that can't be parried. There are actually a lot of contact specials that can't be parried for whatever reason , i.e. Sektor's uppercut and Nightwolf's hatchet. If the attack is particularly integral to that character's movelist (Nightwolf's hatchet certainly is), you're going to be at a much greater risk of being opened up by attacks you can't parry, so this is largely matchup-specific. In either case, this is one of the best tools in Cyber Sub's arsenal, just make sure you use discretion.
- EX freeze is functionally identical to Sub Zero's, but Cyber Subs needs it a hell of a lot more than Subs does. Cyber Sub's ice blast has a longer startup time and much slower travel time, making it harder to land from fullscreen distance. If you're getting outzoned, good use of EX freeze can get you in there. Also, as Pig stated, you can only freeze someone off a 3 3 with the EX freeze; normal freeze is too slow. This applies to several other normal strings where the freeze is too slow to connect while they're in hitstun, though I find this is only useful with 3 3, as it's quick, safe and hit confirmable (albeit with certain difficulty).
- EX bomb is just a guaranteed way to get your opponent off his spot, and if you have the right setup for it, you can pin your opponent on a bomb when they try to get out. I think this is a great tool, but treat it like Sektor's homing missile: Don't throw it out there unless you're sure you can make it count. If you can't, you wasted the meter for nothing. Also note that if you really need guaranteed damage, you can follow EX bomb with EX freeze, which is completely inescapable under most circumstances (I think a fast teleport or armor move might be able to stuff it). In general, I think you should stick to throwing out bombs just to get your opponent off his spot, and only throw the EX bomb when that stops being effective. If it ain't broke, don't fix it. Also remember that throwing out a mid/far bomb after knocking your opponent down (wherever it's safe to do so) and following with an ice ball is often times good Oki, just make sure you can't be punished for it.
- EX teleport is... Alright. I'm really not a fan of this, because as far as I'm concerned, Cyber Sub's teleport exists for the same reason as Cyrax's: It's there to get you in once you freeze/net your opponent from a distance. If you really need this to get out of pressure, feel free to use it, but I believe his meter is better spent elsewhere.
- EX slide is useful for the same reason as Sub Zero's: It goes through projectiles on wakeup and it'll knock your opponent into the corner, if you need it. This is really the only time you should be using it.
- His X-ray is largely situational, as far as I'm concerned. I tend not to use it because EX divekick is functionally identical and does half the damage for one bar, but the X-ray is more advantageous in certain matchups. Because the X-ray has armor, it's really useful in any matchup where your opponent can control space in the air or otherwise stuff the divekick (Noob's upshadow, Ermac's telepush, Sub Zero's clone, and so on). Kung Lao can be a really rough matchup for Cyber Subs because he can easily spin the divekick on reaction, but this shit will make him think twice about trying it.
Hope that helps.