Not much room for discussion there. NoLimits 2 is the industry standard, it is the most powerful rollercoaster simulator out there. But then again; Is there an alternative? The "real" RollerCoaster Tycoon titles, Parkitect and of course Planet Coaster are all video games, they take a lot of liberties with the laws of physics, challenge the player in some way and are of very limited use for real-world designing. There was a semi-serious attempt called Theme Park Studio a few years ago which turned out to be a total joke and Scream Machines is extremely dated and the sequel never made it to the finish line. All those shovelware titles like RollerCoaster Factory, RollerCoaster World (not the "Tycoon" one, although that also turned out to be shovelware) and World's Greatest Coasters 3D are obviously not even worth mentioning.
That being said; NoLimits 2 is by no means a video game! It does its job fairly well, which is simulating and designing rollercoasters on a professional level. But this also means that the software feels dry and sterile and lacks all the charm of games like Planet Coaster. The UI looks bland, it has a pretty steep learning curve and It also sports some weird quirks and workarounds (although far less than Planet Coaster). Also, do bear in mind that custom trains or tracktypes like the ones in the Youtube examples are an absolute chore to implement and require you to work around the systems the developers provided. The application does come with some small scenery objects and flora, but the complex buildings, custom pathways or special effects you see in the movies are all 3D objects you have to make yourself in another program or download from somewhere. There is even a way to script effects and even the behaviour of the coaster itself, but again; very complex. cannot stress this enough, it is a very detailed rollercoaster simulator, not a theme park game. Also, there are no guests wondering around or riding your coaster, which only adds to the sterile feeling of it. There is weather and a full day/ night cycle though, so that's a plus.
Now for the good news, you have full control over every little aspect of the coaster, down to the frequency of the tie placement and individual flanges on the (of course) custom support beams. As I said, it has a bit of a learning curve but I dare to say that it is more accessible and intuitive than Planet Coaster's track builder!
At least you are truly in control here, there are no limits (hey, it's in the name!) to track length, banking, tightness of curves. The way B-Splines, individual roll nodes and the strict splines work is super weird the first time, but after a while you really get the hang of it and it is an absolute dream to build the track the way you want, as opposed to how the game wants it like in Planet Coaster. Changes to the height, banking or placement of already placed track are super easy and will not mess everything up like PlanCo has a tendency to do. And yes, there is a smooth tool (called Depump vertex) here as well, and it actually works for you, instead of against you.
Just bear in mind that designing a coaster might feel more like programming than playing a game. In the sense that the software is not WYSIWYG and you have to run/ compile (Nolimits calls this "Freeze") your work in order to enjoy the result. Most of the time your are just dragging wireframes and punching numbers in dialogs. But the result is ever so satisfying.
