I'm only about 17 hours in so far and only messed with Sanctuary. Just unlocked the settlement next to the dam with the hippie robot, but haven't touched it. I checked the wiki for the available settlements, but they didn't really offer much in terms of a pro/con list. It just gave a brief description of each one. I'm just curious if any users here have more opinions on the subject. Like, which one is your favorite? Which one has the best location? Which one has the best build areas? Any other note-worthy things?

Part of why I'm asking here right now is because I'm looking to build my own skyscraper as a settlement. Each floor will have it's own function(housing floor, food floor, bar floor, shop floor, etc). I'm ready to start building, but I don't want it at Sanctuary due to the small size and that a skyscraper won't exactly blend in too well so I'm looking for a better settlement to build it where it'll "blend" better. Anyone got any suggestions on where I should build it?

So far I'm loving the settlement building. I'm thinking I'm going to go a different theme for each settlement, but I'm unsure what would be most fitting for each.

The only worthy settlements are Vault 88, The Castle and Sanctuary. All the others are just chores to manage and most of the time you'll just forget about them anyway.

Sanctuary is the best though because Vault 88 has so much space it's difficult to build over all of it and The Castle is only available once you take it back with the Minutemen who are pretty much a boring faction anyway, at least imo.

If you want to build a skyscraper though, do it in The Castle is my advice.

Definitely Sunshine Tidings Co-op. I have a mod that turns most of the houses into better housing (which is called Sunshine Township a Tragedy **there are other links if your playing on PS4 or XB1) but overall, I just think it's a nice settlement spot. The mess hall is it's best feature as it plays as a cafeteria while the central building works good for a shopping center/supply spot.

With other mods, such as Scrap Everything and All Settlements Extended it really makes it a great create-your-own settlement.

Now for my own personal base choice, I always go with Red Rocket.
** Unfourtanly since I'm new I can't post the direct links to these mods but feel free to PM if you become interested.