I like the purifiers..
As someone who has a preference to NOS R2R DACs; and who cut their teeth on 90s digital.. (and have toyed with top tier transports et al)
The sound I can pull from 'budget' fi equipment, and 'adding an iFi dongle' does seem to typically gain a tier or so in playback quality from lesser transports.
Of course so many people believe that digital is 'easy' and zeros and ones equal identical playback (irrelevant of transport price), and like to educate others on their beliefs; to the point that majority of talk on the topic is noise from budget-fi zealots who cannot hear differences.. (and demand blind A/B tests, and digitise their vinyl and use hearing aids etc)
My partner couldn't believe the difference a simple dongle made to our hifi..
Lyrics became clear (from Cat Empire to Marilyn Manson) and all music simply became 'more musical' (more nuance and delicacy, more driving power, better soundstage etc)
Traits typically found from a better transport when playing back into appropriate kit.
I recorded a video and placed on a hifi thread, elsewhere on the internet,..
the video was to generate some discussion, and, sadly, all discussion was 'noise' most likely from 'digital is perfect' zealots.
(the norm)
For anyone who enjoys budget fi changes to their hifi rig, that CAN make huge improvements to the sound (for my household, our front end 'transport' massively improved in delivery quality); the benefits of some of these iFi dongles is a crazy bang to buck ratio.. (one of the best purchases I have made,.. and hence have bought five or more unique iFi dongles and filters etc.. none of which are snake oil, irrelevant of the science used to debunk them.. (from people like Amir who was literally the worst eared person on the windows audio team, acknowledged he couldn't hear bitrate differences around 160-228kbps and is somehow the gold standard for auditioning kit... )(my partner can hear overt differences a ROOM AWAY, when I have an iPurifier inline, and she isn't even 'into audio')..
a budget iFi iPurifier upping my transport quality, perceptibly, easily by a tier of audio quality, is quite a legitimate way to save serious coin (and avoid upgradeitis/GAS shenanigans)
Certainly saved me spending big money on cables,.. and THAT is a 'real can of worms' on head-fi and elsewhere....