Unless it's one of those brands intended to last only six months until they change their name from Hung Kung Fui to Chi Chan Chong.
Don't see many of those because when you are running on really low margins the .5¢ extra cost for printing eats into the profits.
I rarely have problems with a branded product although some do tend to be very short lived
I buy a lot of parts from Farmer Tech who previously used the name Arbor Tech which was a trading name of Wengshing Machinery Co .
They split of the public retail which is now called Hutzl , all the same business .
Adding a name to a set of metal moulds can nearly double the cost of the mould so it only gets done when the c\ompany making them is intending to make quality gear & be around for a long time.
Now it is not 100% but I take "unbranded" to mean "untested-lucky dip" and to date that approach has served me well
The second step is to have a look at the vendor
1) do they have a physical address and if the do then google it & look at it in street view
Images on the web of a massive factory but a retail address showing a tiny warehouse in a commercial block don't gel
2) what else do they sell
If everything they sell is associated products then chances they know what they are selling , but if they are selling everything from condoms to maternity bras then they are surplus vendors who just buy whatever they can as cheap as they can with no testing and often sell defective goods.
By virtue of selling maternity bras one might suspect the condoms are not all that good .