What mapping format is best for singleplayer megaWADs?

idk just wanted your thoughts

1. Use the search bar, I'm sure this topic has come up many times before.

2. If you feel that the existing topics don't answer your question, could you add a bit more to your post about what you'd like to understand, or your own thoughts on the matter? "idk just wanted your thoughts" just comes across as spam, whether you intended it that way or not.

3. Some of the options you've listed in your poll aren't even map formats.

4. Different formats have different purposes, what format is best for you depends on what you're trying to do (e.g. do you want your wad to be playable with the original executable?).

It depends what port you’re targeting, and what sort of general vibe you’re going for.
 

Also there’s 3 source ports listed which aren’t really formats, ZDoom, GZDoom and Zandronum all support vanilla, boom, “Doom-in-Hexen” and UDMF.

Here’s an article that might make things clearer: https://doomwiki.org/wiki/Map_format

For me,

If I'm making a more classic styled singleplayer wad I map in Boom Format

If I'm making a singleplayer wad with a lot of modern features I use GZDoom UDMF

None of them.

The author's skill is the only important thing.

As a mapper, I'm thinking Boom hits the sweet spot. Specifically something like prboom+ default compatibility with the UMAPINFO and extended DeHackEd options. Vanilla and complevel 2 limit-removing both have the issue of being finnicky and restrictive, both in terms of line actions and engine behaviour (seriously, some of the bugs I got making 25yoe, or that the Big Ol' Billy-led DBPs were confronted with are just baffling if you don't have intimate knowledge of why Vanilla is so shit). At the other extreme, GZDoom with UDMF has sooooo many features that, unless you're already very experienced and can therefore focus on what you actually want to do, rather than get excited with experimentation, you'll just get bogged down.

Meanwhile, Boom (and probably MBF, and to an extent ZDoom's "Doom format") give you a lot of freedom as a mapper (particularly with generic line types and voodoo doll scripting), but aren't far removed from the simplicity of the vanilla format (there's not tons of extra tabs in the editor, for example). So if you actually want to finish making a megaWAD for people to play, the "easiest" way to do it (even though it's still a mammoth undertaking) is going to be something like Boom, MBF or even using complevel 9 in prboom+ as your limit-removing target level. This way you benefit from raised limits, freedom to make more complex geometry, less bugs, more forgiving engine behaviour (whole blockmap sections won't stop moving because an enemy is stuck, for example) and enough features that you can get creative and go beyond what the base game offers comfortably. You'll spend less time fighting bugs and compatibility testing and also less time looking up how features work and fiddling with all of the millions of options. Chuck in UMAPINFO in some versions of prboom+ (and other ports) and you aren't restricted to the traditional 30+2 map progression, and have total control over things like skies, when text screens come up and more. 

As a player, I don't really mind. They're all good if the mapper knows what they're doing and is making stuff I like to play!

All of them.

lol what kind of question is this, map format has no relevance to how many players i want my maps to support