long? Skip straight to the scores and summary.
EX Holon Phantoms
When Pokémon-ex has been Knocked Out, your opponent takes 2
your turn (before your attack), if Mew ex is on your Bench, you
may look at your opponent’s hand.
(CC) Super Psy Bolt 
(PCC) Devo Crush 
discard 2 Energy attached to Mew ex. If you do, you may
remove the highest Stage Evolution card from the Defending
Pokémon and shuffle that card into your opponent’s deck.
Mew ex is a Psychic Pokémon. This is currently fine:
you’ll have some opportunities too exploit Weakness and will
only occasionally encounter Resistance. The 90 HP is also
fine. Due to Desert Ruins use, you really want this or
110 or better.
Weakness is a pain, but manageable. The main concern is when
you face the rare non-Psychic Weak Psychic Pokémon: that’s when
you are at a serious disadvantage. No Resistance is of course
the worst Resistance, and a Retreat Cost of just one is nice and
easy to manage.
I say it right away: Psychic Vision is probably the main reason
to use this. Just let this sit on your bench and you get to
look at your opponent’s hand once per turn. Its retreat cost is
low enough and HP high enough that it isn’t that easy to OHKO.
Of course, you still need to be cautious since it is a
Super Psy Bolt
is fairly basic attack, the small one you use when you can’t use
the big. While you get a little more than you pay for with it,
since it needs two Energy it’s still only so-so (you can’t use
it first turn, for example). Devo Crush is quite interesting,
and may get this thing played as well: not only does it Devolve
the Defending Pokémon, but it hits them for 50 damage first.
That’s quite nasty on the average Pokémon that “cheated” using
Rare Candy. Even if they are fully Evolved, it’s an easy
finisher on most Stage 1 Pokémon or a damaged Stage 2. Yes, it
requires you discard 2 Energy, but it is rather potent.
Well, I would consider pairing a single copy with the other
Mew ex: you could peek at their hand while using Devo Crush
when you felt like it via EX Legend Maker Mew ex’s
Versatile Poké-Body. Any deck where you really need to see what
the opponent has might consider a copy.
1/5 – Hands change so quickly and it’s too vulnerable in this
3.5/5 – This is actually a pretty general score: seeing your
opponent’s hand is fairly useful, especially since many decks
have a Rocket’s Admin or two, you can actually do
something about what you see. I don’t know if it’s actually
worth using in most decks, but it can be.
4/5 – It’s hurt a bit by being unable to tap into the Pokémon δ
support but knowing what’s coming in Limited is very important
due to the semi-random nature of the format. The second attack
should also prove pretty potent as most players rely on Stage 1
has the potential to help many decks and be very good in a few,
but ultimately it may not be worth the risk.