Hey there
We have a cheap halfords one, its great, does the job – was a gift to be honest so I did not choose personally but my bro bought it after reading really good reviews. Fully agree, it does the job great.
QR mount through the rear axle.
Had it on my superlight a fair few times and its fine, you feel the compression of the suspention a little under braking but thats about it – usually knock the pro-pedal lever up a bit to compensate.
However, do tend to use my hardtail – more because it is set up with road tyres pretty much permanently.
On the HT the rear disk squeals a little from time to time, think this is to do with the QR being pulled around a little and the rear brake on the HT is a mechanical and does not self compensate the pads like a hydraulic setup so no problem really.
Even had the trailer on my singlespeed road bike – not to be repeated again soon as stevew jnr is a formidable lump to move around….!!!
Go for it, you won't regret it.