With LA Mewtwo: 4/10
With MD Mewtwo: 8/10
Pros:
+140 HP with Snowpoint = HUGE
+Psybarrier gives you time to set up against AMU, mirror, GrouDONK, Cresselia/X
+Giga Burn hits the magic 130 mark with Buck's/Power
+MD Mewtwo's Energy Absorption makes Giga Burn easy to use and reuse
+Psyburn OHKOs several basics
+Recover is useful if opp is stalling
Cons:
-2 retreat is a little much
-Discards all energy, not just Psychic, so you must keep attaching to use Giga Burn multiple times
-Snowpoint makes it harder to score easy KOs on basics with Psyburn
Overall, a very solid card that is very under-hyped.