As a player who never before really stepped out of the Standard format, seeing the large differences between the two formats is confusing, even for a veteran player. But, not only the playstyle of the formats differ greatly from one another, but also the values of the cards. While most staples are easy to get, other cards can make even Set Up Shaymin blush in embarrassment. Most notably Celebi Prime from HGSS Triumphant. If you can ever get your hands on one of those, you are very lucky.
Then there is the meta defining card, Junk arm. For a mere uncommon, this card is very hard to get. Excluding Shaymin, some of the current decks in the Standard Format can be build for less “value” than those 4 Junk Arm alone will cost you. Most decks in Legacy do run 4 Junk Arm, as it easily gives you back used up resources. With Junk Arm at your disposal, you can cut back on multiples of item cards, since you can just get them back from the discard pile anyway, if you ever need them again. Junk Arm is pretty much never a dead card in your hand.
Then we have the hated Hypnotoxic laser. Way back when I began to actively play the TCGO, that thing was everywhere in standard and everyone hated it. Now it is in Legacy… and everyone hates it. I can understand why though, free turn 1 damage, possibly even increased by Virbank City Gym, anhnoying sleep and it can be used repeadedly thanks to Junk Arm.
But as much as I hate it, I still use it.
In combination with the Virbank City Gym of course. The deck variation in the Legacy format seems to be about the same as in Standard, though in Standard you are much more likely to find fun and weird decks. In Legacy, most players know exactly what they build their deck for and youll find many strong and well built decks to face off against. Going into Legacy unprepared, will result in easy losses against strong opponents.
In my experience, the Legacy format is slower and more technical than Standard, since, thanks to Junk Arm, many cards or even entire decks are easily countered. For example, a single Lost Remover + Junk Arm can already crush entire Team Plasma decks by removing their precious Plasma Energy for the entire game.
I am still trying to learn how to face off against the strongest decks in the format and I anticipate every match, as I pretty much always learn something new. The biggest difference between the two formats in my opinion, would be that playing out turns without thinking them through before, can already cost you the game. Better prepare for what is impossible to prepare for.
For players who are bored of seeing the same Hoopa to EX benching to Shaymin EX to Sycamore/N first turns of Standard, Legacy is something different to try out. Just be prepared for a rough start, one that may cost you more than you are used to from Standard. I will keep playing both formats for sure and anticipate possible changes to the format like the yearly Standard rotation.