The BogleHeads cult is older than MMM's. And in it's previous incarnation as the Diehards forum at Morningstar.
BH is a cult. Saying "Feck" will get you a warning. Any spicy language will get you banned. The fogies there don't like spicy language, and giving a verbal facepunch will result in a mod's wrath.
But it is the best cult, because lazy portfolios and tons of great resources to read. They have very technical forums, with some smart heavyweights posting there. And then you'll have the folks who ask you to help justify their $5000 Rolex purchase or new Porsche.
I don't have any difficulty justifying a $5000 Rolex or new Porsche (well, maybe the Porsche should be 3 years old to take advantage of the depreciation curve, but for a GT3 or GT4 the depreciation is barely there). I'm glad that this forum has a good spread of financial opinions. Also Rolexes, though not my thing, hold value extremely well. If you pick an asset that holds value well and/or you make it tax deductible (and in my country it's extremely easy to make vehicles tax deductible if you're self employed) then it can be surprisingly cheap.
One reason I think the MMM "cult" is superior to a lot of others is that we allow many, many divergent views. And that's wonderful.
I have unorthodox views in that I'm pretty neoliberal, but I am very rarely flamed on this forum, and I'm never moderated. That's so great. On other forums I've been banned just for expressing my views. I don't think you'll find a post where I'm rude or I resort to personal attacks, so it's not like my manner was personally aggressive. I love the intellectual freedom we have on these forums. It's similar to real life where I hang out with a bunch of pretty cool people and can put up controversial opinions and people recognise it as an intellectual sport, not some sort of personal war.
I agree that one of the things I like about this particular forum (and is severely constrained in both DR and BH) is the freedom permitted to discuss a variety of viewpoints in a civil manner. Tip of the hat to the mods, who help make that happen. It's not easy allowing a lot of opinions while keeping it from becoming a raging dumpster fire (like much of Reddit).
It's weird we've settled into discussing $5k rolex watches and Porches. Personally I have an ethical problem with both - particularly the Rolex. In brief, I don't like luxury objects who's sole function is to signal wealth. A $5k Rolex watch does not perform it's sole fucntion demonstrably better than it's $50 counterparts. IMO at that end of the spectrum it's no longer about style or design, but social signaling (in a very F-you, 'I'm better than you,' consumeristic sort of way).
As for 'holding it's value' - meh. I totally get how luxury jewelry can maintain and even increase their value. As for luxury vehiches... that's been discussed on this forum and typically requires the owner to conveniently ignore a lot of additional factors, like opportunity cost, insurance, maintenance and storage. Every so often a car becomes a classic collectable and skyrockets in value, but the majority don't, and there's (almost) always the requirement that it's not actually driven much and kept in near-new condition. In other words... you can't use your Porshe like a normal car and expect to come out ahead. Those that argue that Porches are 'a better value because they depreciate less' are - IME - ignoring the above factors.