I have both of them.
Be aware that the Stetzer meter only goes up to 150kHz, while the Line Emi Meter goes up to 10MHz, so that is quite a difference.
Be also aware that a lot of dirty frequencies are between 5kHz and 10 MHz.
I like the Line EMI Meter.
For measuring which frequencies are present in the mains, I also use a Spectran 5035 together with a differential probe.
Only a spectrumanalyser can tell w you which frequencies are present, and how stark they are.
It is my opinion that strengths of these peaks in the µV (microVolt) rangte are acceptable, while those in the mV (milliVolt) range are not acceptable anymore, certainly not for electrosensitive persons.
For frequencies above 150kHz, the Stetzer filters do nothing. Here the Bajog filters do work.
But before using a carton of filters (als sales persons by Stetzer recommend falsely) it is much better to first remove the appliances that cause these peaks.
At the end of
http://www.milieuziektes.nl/Pagina12c.html it is stated by Bajog, that more than 5 filters may cause unwanted resonanced in the mains.
So my advice is placing a maximum of 5 filters. If needed more, somthing is wrong and not all causes have been eliminated.