A bit of clarification to my earlier post.
Every hashgacha has +&-.
They have areas where they excel and areas where they fall short. Some are common failings mad some are unique to a specific organization or region.
Even in areas where one excels , there are often anomalies that fall through the cracks (es chata'ai ani mazkir)....
Due to the nature of industrial manufacturing and globalization, It virtually impossible for all but the most scrupulous consumers to research individual products , locations etc to determine what is compatible with their avodas hashem.
To that end , kashrus organizations create minimum standards. Obviously, some orgs minimum standards are different than others which further complicates the subject. To that end organizations like AKO were founded to create a baseline for organizations themselves. That doesn't mean all locations , products, organizations are equal.
If someone tells you that every mashgiach they employ, every location they certify is on the exact same high level, there are no failings, etc, they are either negligently ignorant, lying, or probably combination of the two.
I try- sometimes unsuccessfully- not to publicly badmouth other agencies because, at the end of the day, we live in glass houses. Unless we have determined that said agency is deliberately acting in a way that even they know is detrimental to public standards or blatantly disregarding accepted psak, like certifying gevinas akum and misleading the public about it (extreme example).
Or if I feel that someones understanding of a specific hashgacha is based on a faulty premise...
I was recently confronted about another organization and asked why we don't accept it. I responded as follows.
I don't claim to be more machmir
I don't claim to be a greater talmid chacham (in fact he's definitely a greater talmid chacham)
I don't even claim to have better mashgichim.
We claim to know our weaknesses and have infrastructure in place to address it.
We claim to know who supposed to be responsible for kashrus at every location we certify at any given moment.
We claim to provide mandatory annual mashgiach training for all food service mashgichim
We demand online reporting for every shift a mashgiach works . Most don't get paid without it since it's also the same system they clock in and out with (happy to share what those look like)
We claim to check in on food service location at least once a week, many at least twice weekly and some daily to check in on mashgichim and ensure protocols are being followed.
We claim to recognize our failings and (hopefully) address them adequately.
That said, we recognize that there will be variances from place to place
When someone inquires regarding the acceptability of our kashrus, I'll often ask them what are their personal standards at home. If they rely carte blanche on their local Vaad and eat at restaurants with any national hashgacha, they can rely on our certification carte blanche. It's not to say that there aren't variances but rather the derech they've chosen to follow . There's not necessarily anything wrong with that as mentioned above. That's why organizations like AKO, cRc, and others have created lists which are hopefully based on adequate research.
If someone asks a specific question, whether it be regarding PY/BY standards, Yoshon, toila'im etc... we respond a accordingly.
To start comparing individual hashgachos without specifics is not really helpful because many of us who re involved with these hashgachos often have different experiences.
To that end I will not respond publicly regarding the question of BDMC/TBD is a 'better' hashgacha than RYB because my experiences are likely different than other people experiences. My first hand experience with one of them and that likely colores my judgement.
I recommend as follows....
If you have specific hanhagos, educate yourself in how to ask questions related to those hanhagos.
If your part of a specific community, reach out to the regional leadership of said community.
If your a litvishe yungerman, a call to the local rosh kollel is probably a good first step.
If your affiliated with a modern Orthodox community, reach out to the leading community Rabbi.
If you're a lubavitcher, find out who the local shluchim follow for psak .
For all the above, don't rely on some random person of your affiliated community who personal hanhaga doesn't reflect the reality of what you should be doing. Even if he's a good friend of yours....
In our community, I think people might be surprised to hear what the most respected shliach (as a talmid chacham and Dayan) or the Kollel rabanim, or leading Modern Orthodox rabinate (in fact they're pretty closely aligned across all communities) has to say about the practices of the hamon am....more on that another time.