Similar to Latias EX, Latios EX is a Dragon-type card with awkward energy requirements that hits for awkward damage numbers. Its HP, type, weakness and retreat cost are all reasonable, so let's take a look at its attacks.
The first attack: retreat-locking is sometimes relevant but really, for a 2 energy attack (that can't even be a DCE) you could just be using so many better EXes. Mewtwo EX's X-Ball will be more useful than this in 99% of the situations I can think of. Let's not forget that most of the meta decks run Keldeo EX + Float Stone to prevent getting retreat-locked as well. Also, 40 damage is extremely low in a format where most things have >100 HP.
The second attack is alright and can cause OHKOs, even on EXes, with the help of a Laserbeam, but requires a combination of Energy that's pretty rare. It's one of the combinations not found on the Blend energies, which makes the card hard to fit into a deck. The downside is also pretty harsh, which leads to the following topic: the support for this card.
Getting 3 Energy onto a Pokemon is relatively slow without any support, especially when you're forced to toss all of them when you attack. You could use Blastoise BCR with this to get the 2nd attack loaded in a single turn, but at that point I think it's clear that Black Ballista Kyurem EX is just a way better option, leading to guaranteed OHKOs even without a Laserbeam. If you just want to hit for big numbers, then there's already Kyurem PLF + a couple Deoxys EX on the Bench doing a fine job and with an easier energy requirement, plus all the Plasma support to go with it. Something like Zekrom EX + Eels does a better job at hitting 150 constantly as well.
Rating: 2/10
I think this guy has the unfortunate fate of being outclassed by other cards, not only in PLF but also in older sets.
If you want to build a control deck about retreat-locking, then there's Deck & Cover Accelgor or even Articuno EX doing a much better job.
If you want to OHKO EXes, then there are Rayquaza EX, Zekrom EX + Laserbeam, Kyurem PLF + Deoxys EX + Laserbeam, or Black Ballista Kyurem EX all doing that more reliably.
If you want to hit for 40 early, then Mewtwo EX + DCE is obviously superior.
This card has nothing extraordinary going for it and that hurts him a lot. I'll say the fullart looks pretty sweet, though.
