I've got both an MR100 and a nanoVNA. The MR100 I got several years ago. It has issues with the output from time to time and it sometimes gets stuck on max VSWR (10:1). I use my notebook with software built for each of them and get really nice pictures of the sweeps. I would tend to rate the nanoVNA above the MR100 for sure. I love both of them for what they can tell me about my antennas. I've got a G5RV Junior antenna as a center fed inverted L (more or less) and I want to tune it better. I got useful readings from both and compared them. However, I did that in the shack and I am pretty sure I'll get some different readings at the feed point. I've got a current balun some fifteen feet from the transition to the 450 ohm window line so that ought to be a superb place to connect. I can run them off my notebook. If I need extended time I can run an extension cord around the house to the measuring point. What a fantastic tool for us ham radio folks!