I too have the NS1201SA and a NanoVNA-V2.
The NS1201SA has a large, easy to read display that’s great for working outdoors and a nice, rugged aluminum case. It has a minor downside in that it has only 1 calibration profile and it takes a while to calibrate it. It also doesn’t have a PC interface which may or may not matter to you. There’s also very little in the way of support.
The NanoVNA V2 is an open source (both hardware and software) device and can be purchased from different vendors with different screen sizes. It has a steeper learning curve but has the capability to save different calibration profiles and has 2 RF ports for testing things like filters. It’s hard to use outdoors BUT it has a USB interface and companion software that let’s you use the device from your PC. That’s a great feature if you want to save screenshots of tests and you can configure it to show multiple graphs at once. Support is also available via groups.io and the designers are very responsive. Oh, there are 2 versions, the original with the RF ports on the side and the V2 with the ports on the bottom (or top depending on whether you rotate the screen). Get the V2. Also most vendors ship a non-enclosed unit with only front and back plates.
So, I use the NS1201SA for outdoor use and quick (but perfectly functional) tests but use the NanoVNA-V2 on my workbench where I have a laptop set up. Either way, get a calibration kit consisting of Open, Short and Load terminations. Many NanoVNA vendors toss them in as part of their offering.