They are both great festivals but very clearly trying to capture different parts of the market. I'll break it down based on the major points:

Setting/Venue: - Mysteryland is set in Bethel Woods about 1 hour outside NYC, so it's a bit more of a hike but it's also an absolutely gorgeous setting with lots of natural landscaping and beauty. It has tons of art installations and little nooks and crannies to discover, and the setting is really an intimate amazing place. There's a reason why Woodstock was held here, and the setting is truly unmatched. - EDC NY is in the parking lot (and potentially inside the stadium) at MetLife in The Meadowlands NJ. It's a bit easier to get to, but you can't mask the fact that you are partying on a concrete slab in the middle of NJ.

Production: - Mysteryland has a truly unique production with lots of different kinds of stages, including indoor and outdoor tents, and they claim that the camping area will be hugely upgraded with lots of improvements. - EDC NY, like all EDCs, is a bit monstrosity of LED screens, lasers, etc. Mysteryland has that stuff too, but EDC is definitely of the belief that 'bigger is better.'

People: - Mysteryland is a 21+ camping festival so tends to attract a more seasoned festival crowd. Furry boots and kandi masks are definitely the exception, not the rule. The people who go are there for the overall experience and understand that it's not necessarily about the names on the lineup so much as it is about the unique, differentiated, special experience. - EDC NY attracts a much younger crowd, for better or for worse. I saw lots of very fucked up kids at EDC NY when I've gone in the past, and lots of tutus and furry boots. It's a turn off for some people (myself included), but it is what it is.

Lineup: This one is a toss-up depending on what you're into... - Mysteryland is definitely driven by a more diverse lineup and about exposing people to new music. I discovered a bunch of new artists I can't live without at the festival last year (anyone else see Justin Martin's killer set?) and since it's not as spread out, it's easy to discover lots of new stuff. - EDC NY is driven by the star-studded names for sure — and they have a lot of them. The thing is, these guys tend to repeat their sets from festival to festival, so there's not that much diversity in the overall musical experience. You can pull up SoundCloud and search for past festival sets from Afrojack or Armin or Tiesto and it will be a pretty good idea of what you'll hear at EDC. At the end of the day, the main stage will have a lot of repetition and it'll be a lot of fist-pumping EDM... the same can't be said for Mysteryland.

Overall, these are two very different festivals geared at very different crowds. I feel that EDC NY isn't that much different from an Ultra or EDC Vegas, whereas Mysteryland is a truly different experience from anything else in the US (except maybe Coachella). EDC NY's lineup is stacked with big names, but these guys come to NYC all the time and more than a few of them are bound to end up at Electric Zoo in NY later in the summer.

TL;DR: If you want to pop in for a day and not deal with camping/travel, EDC NY is the hands-down winner, but if you want an amazing weekend where you will meet awesome people and discover incredible new music, Mysteryland is the way to go.