I make efforts to judge techniques or DVDs not the creator's merits, but on their substance. So, even if he's not a big competitor, and he hasn't produced any ground up standouts, I try to only consider: is this material good? Does it work well? Sometimes really great competitors put out jank shit that doesn't work as DVD filler (or doesn't work for anyone who isn't them). Sometimes people you've never heard of change your life. At the end of the day, it's all about the quality of the material. Is it mechanically sound? Is it going to work against competent opponents? Or is it shenanigans?
Going through Melanson's library is a mixed bag. He teaches good fundamentals, and he does correctly address some good concepts in his set. I.e., breaking posture, looking to set up the triangle with off balancing, making sure you're pressuring in the right directions. There is a decent amount of, as of current knowledge, good advice.
But he also does a bunch of really weird gimmicks. This is purely from an outsider's perspective, but it seems like he was trying to be the catch wrestling Eddie Bravo. He doesn't have the same "dude weed bro" draw (though the old timey strong man mustache vibe may be his meal ticket?), nor does he have a noteworthy victory over another competitor on which to sell his platform. Instead it's just gimmick for the sake of gimmick.
By that I mean he'll take a position so normal as to not really warrant a "guard" status (head control, for instance), an already existing position (shawn williams guard, or in Melanson's vernacular, "shoulder pin guard"), or create a position/move predicated on just being long (manlets need not apply), and add a cool catch-style sounding name. Some "chokes" end up being cranks or pain more so than pure strangles. Some finishes are little...far fetched. I get it. He's trying to sell his brand. But if a gimmick doesn't produce results, it's not going to catch on. I also don't buy the "it'd work better in MMA" argument (I didn't buy it for rubber guard either, as it seems like excuses for nonperformance in grappling either way). While I believe that mechanically grappling is grappling (just because you do catch or judo or sumo or bjj doesn't mean my body or physics work any differently than before), I understand the philosophies to enacting those mechanics can be different. But this is a branding qualm, not a philosophy qualm.
If you have a discerning eye to separate fact from fiction, the set does have solid information in it. I can see if you're someone who has too much pride to learn from a BJJ set (or if you have grappling-hipster-syndrome) the fact that it's marketed as "catch" would make it more appealing. Moves like the "butcher shop choke" sound pretty cool after all. But otherwise, if you don't have such a bias, there's no reason to get it over other grappling sets that don't have the gimmick/fluff. Also probably a good idea to get a set with less of a focus on closed guard, which is neither played in grappling or in MMA at the high levels any more.