LibreVNA, as I have probably mentioned, is not an ideal product.
However, at this price point, it's hard to find any good VNAs. If you only care about antennas, you can easily try the cheaper LiteVNA recommended here. If you are thinking about something more and need more dynamics (e.g. filter measurements) I would choose LibreVNA.
The Siglent SVA is a nice product, but the VNA as I wrote is just an addition to the spectrum analyzer and does not have great parameters.
Personally, I bought a Siglenta SSA3021X Plus without even thinking about the VNA, it turned out that I can easily convert it to SVA1032X by changing the firmware - so at this price I cannot say a bad word about this equipment.
The sad truth is that you have to pay a lot of money for a good VNA (even a used one).
I think a bit about the Siglet SNA5000 myself, but I will wait for more opinions about this equipment. Probably at a similar price I will look for other solutions in the future (although I am afraid of buying expensive used equipment online - it's easy to be deceived and buy faulty equipment). I have already bought a damaged HP spectrum analyzer (it was supposed to be operational), after thorough tests it turned out to be damaged
. On the other hand, the cost of parts on e-bay is so high that it doesn't pay to repair it. Maybe someday I will find a similar one at a low price to take apart and I will be able to run it
So if you only care about antennas, I think you can trust
joeqsmith's opinion and see how LiteVNA works (especially since it's a small expense). Watching Brymen 869s multimeter tests on Joeqsmith Youtube channel I decided to buy this meter and I am very pleased. So I think you can rely on his opinion on LiteVNA.