Re the digital filters, normally I find the sharp/fast roll off a little well sharper and thinner. And the slow/gradual roll off usually more bassy and full.
Not a big difference, basically just cutting off different parts of the wave. I do find these have a little more effect than the ess ones. I'm using fast roll off and phase compensated on the R5.
I don't put too much emphasis on dacs, after all they're all just crunching numbers but the filters and software give them their own flavour. I feel the amp and LPF is really where the sound is shaped.
However, I really like the basic tonality of this cirrus. It's a good blend of emotional and resolving. The sr15 has some added colour in the mids, and the R5 has a bit added in mid bass. From the general consensus the dx160 is less coloured which should sound really good with this dac. Assuming the amp stage is solid
I'm sure it is