I've read all that about usb tuners too.
My usb tuners are warm when in operation, but far cooler than my laptop and are cold quite soon after recording. PCI tuners are probably cooler because you have a case fan cooling them.
I gather that in some countries they have their tuners running 24x7 to grab EPG since they only have now+next, hence their tuners get warm from constant usage. Whereas in the UK, the EIT is easily retrieved during normal recording since it's broadcast on all channels. So maybe the usb is lower quality/warmer but it doesn't matter as much since your tuner might only have a few hours a day usage at a time, whereas in those countries maybe the constant 24x7 usage burns it out sooner. Or maybe it's just a myth.A poundshop usb fan would probably cool the usb cards just as well.
The usb tuners I have seem no different in quality to me than the tv, so I get occasional pixellation with the tv, all of the tuners, even with the dvb-s2 tuners. When watching a recording I can not tell with which tuner it has been recorded, which is as good a test as possible.
My tuners are often in operation for a good portion of the day since different people watch different things and we often record things that we only actually watch if we're in the mood or if specific people visit.
I think my oldest usb tuner is about six years old, made in China. I've had no problems with any of my tuners, but you never know if I'm lucky.
You pays your money and you takes your choice.
