When it comes to memory, there are basically a limited number of actual chip manufacturers - in DDR1 times there were about 6, companies like Inifineon, Samsung, Hynix, Elpida etc. Everyone else just bought buckets of their chips and stuck them on their own DIMMs. Now, the way they did that also affects things like reliability and compatibility. but really they could only mess things up, not make anything better, and the most important characteristics still come from the chips themselves.

In addition, some 3rd party vendors had an alarming habit of switching chip vendor but keeping the exact same DIMM models, meaning that you had no idea what you were or are getting.

So personally I'm a great fan of buying DIMMs from the chip manufacturers themselves. If memory is from a 3rd party, the first question is which chips they have used on the particular DIMM you are considering buying.