HI,
there are several things you have to reconsider when asking about a good brand for memory.
The first thing is the SPD programming. If this is done wrong, then your system can have a lot of problems with the automatic DRAM timing settings. I have read several tests of main memory, that showed, that a lot of SPD EEPROMS are programmed wrong.
But this one should be the easy task.
The next thing ist the layout of the PCB. Here can be made a lot of mistakes too. Especially, as for SDR and DDR there is no official spec that it defining the DIMM timings exactly. For this kind of memory only the device timings are exactly specified.
In addition to this, the PCB should be designed to fit the devices used on it.
And the last (and for me the most important thing) are the used devices. Here you have several different things, that work togheter.
If you have an older device (like the older 64Mbit generation) you can get a lot of different technologies inside the chips. For the first generations of a memory chip, the die size is quite large (because of the older technologie), and the design might still have one or the other bug. With improvement of technologie the die size will be smaller, the chip will be faster and maybe the bugs fixed ;-)
But on the market you will find always DIMM of the same size, but with different technologies. And it is not really fair to compare different devices.
e. g. if you have two 128MB DIMMs, where one is based on 16 x 64Mb (double sided) and the other on 8 x 128Mb (single sided) devices the double sided will be better for overclocking if they are built with the same technologie. The 64M die will be smaller, and will have more margins for OC. But if the 64Mb device is older technologie, it is maybe much slower then the 128Mb ....
Because of this reasons, it is quite hard to define the best brand. Every brand will have some week designs in its programm.
Therefore I like to have a DIMM, where the manufacterer give the information about the design of the devices, and is having a detailed datasheet to the DIMM. Because this is the most important information that you need to define wheter this is a "good" or a "bad" DIMM. If you have no information on the devices used on a DIMM don't buy it, as it can use different devices, where one DIMM will work fine, but the other will always make problems.
Therefore I would vote for any DIMM, that is made completly by a DRAM maufacterer like Micron or Infineon. As they know if a device has any problems, and can support this by a good PCB layout.
bye
ruckb