I have had both. In fact, I sold my Puritan (which was very good for the price and far better than the Nordost that I owned initially ) for the Denali. The Shunyata provided a lower noise floor (indeed silent), clearer, more articulate, tighter bass, more separation of instruments and a larger soundstage (especially in depth). Tonal/timbre of instruments was better. Note that I was using the top of the line Puritan power cord with the puritan and a Shunyata Sigma power cord with the Denali. Separately I compared the two power cords and the Shunyata was clearly (pun intended) better. Of course, the Denali is several times the price of the Puritan but you do "get what you pay for."
The Denali with the Sigma power cord (both often found used) definitely will increase the detail and improve the tonal quality of your system.
Incidentally, run ground wires from components to the Denali or get the Altaire grounding system... it does help.
