Signalyst HQPlayer - Is it worth the upgrade?

Why don't you check for yourself - HQPlayer has 30min trial, and after that you just restart the app to continue listening. Plenty of time to evaluate. 

Also, your sentence "actually compared Roon vs HQPlayer or using HQPlayer exclusively" doesn't make sense. HQP works WITH Roon, as addon, and does upsampling, even though Roon has its own upsampling DSP, but HQP is much better. So those 2 apps can't be compared directly. 
Sure, HQP can also be a player, but its not really its selling point, it can't be compared to Roon, not even close as a player or music catalog. 

Benefits of HQP solely depend on your system, what kind of DAC you have and will it benefit from the external upsampling, does it prefer DSD or PCM, do you have powerful enough computer for DSD, whats the resolution and transparency of the rest of the system... So, you just have to test it your self, opinions about HQP setup here are very individual and will be very different from what you'll hear. 

@designsfx 

Thanks for the link. I will definitely check it out, looks like lots of good info there. 

Update: 

I got my HQPlayer up and running as of yesterday.  After 6.5 listening session and few adjustments with default filters/modulators, I found my favorite tracks through HQPlayer clearly had more texture, tangibility, richer tone and detail vs Roon. I was skeptical going in but this is indeed a very nice upgrade over Roon (audio). There was no hint of superficiality and edginess that I experienced through Roon…..no listening fatigue whatsoever with HQP. 

I tested lot of my of favorite tracks ranging from 44.1kHz to 192kHz, streaming from Qobuz and my local files, they all sounded more lifelike through HQPlayer vs Roon. As far as DSD tracks, I didn’t like what I heard. To my ears, the DSD tracks sounded compressed…it could very well be the filters being used. 

Moving forward, the biggest challenge I see is finding the optimal settings between Filters and Modulators with different resolutions and as little impact to the original bits. For now all I can say if you love Roon and stream via Qobuz, you gotta hear HQPlayer in your system. 

My total outlay so far, $525 (mini PC off Amazon plus HQP License fee). Mini PC is currently powered through stock wall wart. I will add JCAT Optimo 3 Duo LPS in the mix once I gain better understanding on gamut of filters/modulators included with HQP. 

Late to this string but was doing some research.  I tried roon+HQPlayer and Audirvāna.  I was so impressed with HQplayer I bought the desktop version but after checking out Audirvana there is no doubt in my mind when it comes to clarity, texture dynamics etc. Audirvana is better to my ears.  I highly suggest trying out the trial.  It has its quirks - no convolution built in like roon and hqplayer but it is clearly better than roon and tidal and qobuz apps in how it presents the music and  it works with dlna so it is more versatile than both roon with roon cert endpoints and hqplayer naa.  I feel bad I dropped near $300 on hqplayer but hoping they will let me trade it for hq player embedded which works with  dlna to get the best two of the three apps and will be dropping my roon sub as soon as translate some my playlists over.  Just wanted to share my experience.

Did you try all possible filters? I have been following the AudiophileStyle forum too and understand that there are tons of filters you can apply. Might be you want to reach out in that forum and identify the one that might surpass your expectations. Now that you already invested so much, why not give it a shot? If there are folks here who have achieved what they like with HP Player, hope they read this thread and share their filter settings with you.