A rare event: I have found an NMR program that's been a pleasure to inspect. It comes with an HTML manual (with pictures) and sample data. These two ingredients remove the usual obstacle for learning (you rarely guess right how to arrive to a frequency domain spectrum). In this case, instead, I could easily open one of the included sample spectra, because they come with their own processing scripts, and experiment with the buttons (relying on the help of the yellow tips). It's clear that they spent their time and money in making this program. It's well done.
The program is called ProSpect ND and comes from Utrecth. It's completely free. In theory, it's cross-platform. I have tested the Windows version.
Why isn't it more famous? Well, to start with the name, it is focused on multi-dimensional spectroscopy and favors serious processing and flexibility over simplicity of use. You realize this fact from the very beginning. To open a spectrum (Bruker or Varian, no other format is recognized) you must first convert it into the ProSpect format with a script; it's not trivial.
The program also includes all the routines to process and analyze a 1D spectrum. The graphical layout is, well, arguable. For example, the peak-picking labels tend to overlap with each other.
Speaking of 1D, LAOCOON is also included. Forgive my personal reminiscence: the manual doesn't refer to the first version, as everybody else has always been doing, but to the the last version by Cassidei and Sciacovelli, who happen to be the ones who teached me how to use a spectrometer (and some theory too, in the case of Sciacovelli).
My first impression: they have written a program the way they like it. If you need to print your 1D spectra, I bet you'll have diverging opinions. If you like to spend much time in 2D processing to obtain the optimal results, and the other free alternatives don't satisfy you, chances are that ProSpect ND will.
This product confirms the rule: it takes time and money to make NMR software. If you want it free, you must find a sponsor with large shoulders. There's an important difference that puts ProSpect apart from more famous free programs like the original Mestre-C, NMRPipe, SpinWorks, NPK. Prospect is open source. In the case of NPK I may be wrong. Anyway, you can directly download all the source code of ProSpectND without asking any permission, without registering, without logging in. Guess the language? Phyton? Noo! Java? Noo! C++? Noo! OK, here's an hint: the first date on many source files says 1997.
C? Yes, I like it!