My main interest would be the M HEROs, but aside from that, there are a couple of other cards that caught my eye.
The first one would be Rosalian. While its effect is not necessary what I would say amazing, but it has its uses. Once per turn, negate the effect of all other face-up cards till the end phase. A few example how this effect would be good would be attacking No39 Hope, or playing a trap while Decree is up (I think thats possible, although I'm not 100% sure, please update me on this one.). The main reason I took interest in Rosalian is his summoning condition.
You can special summon him by banishing a level-7 or higher Plant from your hand or graveyard. Kinda like Hyperion but slightly bigger, at 2900, his no joke. What makes him good is that he is a level 8 Plant himself. While he can't be special summon by Lonefire, this card gives you another reason to play Tytannial. Maybe as another boss monster for Skill Drain Barboros? Like how Eatos was, only Rosalian is less situation late game and is bigger. Overall, I say his one of the cards I would definitely try out.
Ma'at as a Secret Rare sucks, its either Ultra or don't print it at all. They've already ruin E HERO the Earth years ago as a secret and not naming him The EARTH (his name is in katagana, unlike the other Planets).
Orge Dragoon serves as another boss for Infernities, but I highly doubt Infernity has space for it. Since they run 3 Hundred Eyes, Brionac, Trishula, Leviair, Chain, Emerald among others. Well, I'm not that familiar with an Infernity deck's extra, so I'm not one to bitch.
Being a 3000/3000 (almost) generic beatstick is good. And he is a Shi-En under handless situations, that can't go wrong.
Photon Sanctuary may seem to be a Photon Imitation of Stray Lambs, but its actually pretty good, even outside of the Photon archtype. The negative effect of the card, is unlike Stray Lambs, where you can't summon at all, you can't summon anything thats not a Light monster. That basically solved everything Stray Lambs was deemed useless for. Not being able to be used as a syncro material is good since Formula and Quaser are both Light.
The tokens themselves are pretty beefy, 2000 each. Means you can now drop Galaxy Eyes without even normal summoning anything. A huge leap from what ORCS gave us. Photon Wyvern also has its uses because of this. Unless your opponent has a Solemn set, his very likely to have his whole field nuked 1st turn, and since this is normal summon, Rai-Oh doesn't do shit. I say, if you plan to play Photon (or rather, Galaxy Eyes), get a play set of this. I see this being played in other decks as well, namely a token deck, which I've been planning to build since DREV.
Now, into our topic of interest, the Masked HEROs.
The 2 M HEROs released in PP14 makes the 2 from PP13 look like jokes.
M HERO Acid's effect is simple, he can only be summoned by Mask Change and when he is, he blows up ALL spells and Traps your opponent controls. AND all their face up monster loses 300 attack. This has to the one of the most devastating effect from a HERO since Absolute ZERO. Like how ZERO brought HEROs into the competitive scene, this would be the HERO that would make Mask Change playable.
The 1st effect needs no introduction, destroying all spell and trap upon summon is an extremely powerful effect, the only thing that might happen to you would be BTH or Torrential. Well, if you took out 2~3 cards, its fine. Solemn Warning and Judgment does NOTHING to this card, keep this in mind. Your opponent has to negate Mask Change, and sending a HERO into graveyard isn't a cost, you only do that upon resolution. So, IF your opponent has Solemn, it would be a 1 for 1, where you treat Mask Change as MST, while your opponent loses 2000 life.
The 2nd effect may not seem so powerful, BUT it has its uses. Acid is 2600 to begin with, so its gonna kill anything thats under 2800 upon summon. Although your most probably gonna use ZERO as the tribute fodder and blow up your opponent's field.
Because of this, I'm considering playing 3 Mask Change instead of the 1 I'm playing right now. I really do think Mask Change is an amazing card, its won me a lot of games up till now, and I only had Vapor and Gokka to work with. I've seen a lot of people misplay this card, kinda like how most players don't know when you should play Gemini Spark or Super Poly in HEROs (especially when they play my deck). May discuss about this some other time.
The last card I want to review, would be M HERO Daian. And I would say, this card is AMAZING. While you would most probably play 1 copy of this in your extra, unless your running some sort of Earth based HERO deck (which isn't half bad, cause Wildheart is 2500 under Skyscrapper and Blade Edge is a 2600 piercer thats is free to summon most of the time).
Daian is 2800/3000 (a 3000 defend HERO is good since we don't really have a generic wall, but thats sarcasm I guess). When Daian destroys a mosnter by battle and sends it into the grave, you ... special a level 4 or lower HERO from deck ...
I guess Konami decides that HEROs doesn't have a good search engine and need a bigger shura/firedog then. This card is good when you need to push for game, see this happening quite often. HEROs usually face 1 problem when trying to push for game. The right monsters on the field. What this card does is it searches out the piece you need and win the game from there. If you play Fusion based HERO decks (Miracle Gemini is NOT a HERO deck!!!), you would have face this multiple times. Having those big powerful quickplays in hand but not having the right HERO out, and you would have to minus-one'd yourself to get rid of what ever your opponent has on his field. Well, this card answers that question, and with 2800 attack, it answered them very well.
I may be a bit bias on the 2 M HEROs, but that just showed how excited I am knowing these 2 would be release soon.