Yes over the years members have done extensive tests on them and they have always faired well. I have a fair amount of free plugins but the vast majority are from well known developers that provide them to entice one to buy their paid for plugins. Its a way to advertise without being blatant about it. But I wont compromise my system to run 32 bit free plugins when there so many 64 bit ones out there. Then I am a strong user of PC modules which in a lot of cases replace plugins that may cost a lot more.
The only plugin from CW that I have very little respect for is Boost 11. It was not meant for Sonar Producer but members demanded it to be included and CW did include it.
CW has always tried to provide quality plugins for its flagship DAW. Most new members are under the impression that because these plugins are given away they must be second rate. That is a mistake.
I have use a number of DAWs through the years and no other DAW comes with the plugins of comparable quality. Not Logic not Cubase and certainly not Reaper.
The Sonitus ones are unique in that they are quite capable of emulating many other types of well known hardware FX. Or they can be transparent. However one has to experiment with them to know this.
In the end though what Beepster and Scook posted is more to the point and should be taken very seriously.
You need a stable system to get the most out of what you already have.
Up your RAM to at least 8 GB and I think a lot of you troubles will fade into the past.