I'm also firmly in the "6-3 with bonkers decks" camp.
I'll go ahead and cobble together some of my thoughts on RNA draft into this post.
Format speedNoticeably slower than GRN, but still faster than M19/DOM by a reasonable amount. Overall, I'd call it 'moderately slow'.
Guild / deck tier listTL:DR: Simic >= Orzhov >= Gruul > Rakdos >= Azorius
IMO all of the guilds are very close in power level and provide a functional game plan.
Simic might be the best guild overall if it comes together; being able to play virtually any end of the midrange spectrum to pretty good efficiency.
Orzhov has access to the highest power level cards in general, but can have problems closing out the game quickly.
Gruul is the best aggressive guild, having ways to punch through damage even through mid-range boardstates (which are very common) while not being helpless in longer games thanks to access to big creatures.
Rakdos keeps most of Gruul's aggressive firepower and maybe has some more, but is more prone to running out of gas and thus in a worse position considering the midrange metagame.
Azorius is in the weird spot of wanting to be a tempo guild while having the Orzhov problem of not gaining enough closing speed. Most of Azorius' creatures just don't deal enough damage while not being big enough to block the bigger creatures.
I've excluded the Gates deck from this list; mostly because even if you're Gates, you're generally basing it off the most open colour/guild (most commonly Simic, but I have seen every guild bar Rakdos as the base) and need to find enough payoffs for it to be worth it. That said, it can be a deck.
The mana situation and splashing In general, it's a bit easier to splash in RNA than in GRN; mostly because the format is a little slower while providing a similar amount of fixing. That said, due to the restrictive mana costs it's generally best to stay 2-colour if possible and only splash for an absolute premium card.
An exception is the Gates deck, which can splash anything given the correct gates/bombs, but that deck is somewhat tough to pull off IMO.
With the format being rather slow, I don't mind running up to 3 Gates in virtually any deck (aside from the most aggressive Rakdos decks, but Rakdos is better if you are in the midrange camp IMO). If you have Gate payoffs or are splashing you can up this number slightly.
Most decks want 17-18 lands; bear in mind that
Open the Gates basically counts as a Guildgate/
Gateway Plaza (I've had the ol' 15 land 3
Open the Gates manabase before)