Had one for a few months from Tredz for £80 or so.
Overall I really like it, coming from a Maverick Speedball its a revelation!
It isn’t as ‘nice’ as a Reverb etc, but at less than half the price I wasn’t expecting it to be. The lever is as good shape and actuation is quick, although it took some fiddling to get the seatclamp tension right for this.
Only concern is with the cable entry ‘noodle’, it doesn’t look very neat and seems to keep the cable close to the stanchion which may cause wear over time.
There’s a new Bikeradar video comparing the RSP and Eten which pretty much sums up my views. The Eten gets a few criticisms which are the reasons I went with the RSP.