Most ram comes with a lifetime warranty.
It probably is a good idea to stick with name brands that have a support system that is available to you.
In selecting ram, you want guaranteed compatibility.
If you should ever have a problem, you want supported ram.
Otherwise, you risk a finger pointing battle between the ram and motherboard support sites, claiming "not my problem".
One place to check is your motherboards web site.
Look for the ram QVL list. It lists all of the ram kits that have been tested with that particular motherboard.
Sometimes the QVL list is not updated after the motherboard is released.
For more current info, go to a ram vendor's web site and access their ram selection configurator.
Enter your motherboard, and you will get a list of compatible ram kits.
While today's motherboards are more tolerant of different ram,
it makes sense to buy ram that is known to work and is supported.
At equal speeds, lower cas is good.
Such ram will also cost more.
There is a balance.
Interestingly, If you divide the speed by the cas, you will get similar results. The importance of cas vs. speed will depend on how your apps use ram. Since this is probably unknowable to you, I would not worry much about it.
Whatever you do, buy a matched kit.
Separate sticks are not guaranteed to work, even from the same part and lot number.
Consider this up front and do not plan on adding ram in the future.
Unless you are seeking record ram overclocks, fancy heat spreaders are not important.
They are mostly for marketing purposes.