Chernobyl is my #1 mini-series GOAT.
That said, mini-series pilots should be in a separate category from regular series.
Mini-series have a clear beginning, middle, and ending within a far lower number of episodes than regular series and have different standards of storytelling.
Mini-series basically cinematic novels - episodes are chapters - and the pilot is the 1st chapter. Regular TV series are like many-books long series and the pilot is the 1st chapter of the 1st book.
Kinda like how GoT's seasons were adaptations of each book of the ASOIAF series.
I would separate miniseries, too, but for the sake of comprehensiveness when compiling IMDb ratings for other Sherdoggers' to study for their own pleasure, I didn't want to leave it out, and left those judgements to them.
There's a bit of funny business there, too. Awards ceremonies call them "Limited Series", and
Fargo famously avoided contending with the other heavyweights at the Emmy's, most notably
Breaking Bad and
Game of Thrones, by applying within that category. One could argue that this is justified because each season tells its own story with its own characters, and there are almost no crossover with other stories besides a tiny few Easter Egg references from the shared location (Fargo, North Dakota) to historical events, building, items, or characters shown in the other seasons. FX calls these "anthology limited series".
https://www.writtenby.com/webexclusives/rise-of-the-miniseries
In the 2010s, for Emmy voting purposes, the Television Academy began referring to any show over two hours as a “limited series.” Still, some networks consider anything less than four hours as a “miniseries,” and over four hours as a “limited” or “event series.”
Further complicating things, there have been projects in the past which were originally supposed to be a miniseries, but were popular enough that they expanded into a regular TV show by serializing additional content.
Big Little Lies is a recent HBO example. My own nominee,
Battlestar Galactica, is one of these. The made-for-TV "movie" that became so popular the SyFy network decided to follow it up with a series was actually shown in two parts like a traditional miniseries.
And now I realize I totally forgot to add
Roots to the list.