From what I see Realphones System-Wide works similar to how Sonarworks Reference, ODeus ASIO Link and VB cable work on PC, between the ASIO driver and the direct CPU calls to the operating system. But RP has a lot more audiophile centric features that are needed for mixing.
I have a EGA Nu Audio sound card, Sonarworks demo was constantly fighting with Nahimic driver of my Nu audio card introducing latency for some weird reason.
RP System-Wide has been very hassle free with my setup Nu audio, FL studio, AKG k240m2's. The latency is within a normal range.
I have clear sense an audio engineer has been working on this, the speaker response emulation is awesome. It sounds like bass drum kick is coming from floor and not in your head, some real interesting acoustic modeling going on, it reminds me how Airwindows VST "Monitoring" plugin's 'Cans' settings worked. I found myself very easy just to listening to music without any fatigued at all when using RP. FL studio has no problems with it.
For PC it is a very good headphone monitor emulation system, I've always used headphones. It's exactly what I needed, other people mileage may vary.Read Review
I've been using Realphones for a few years now, since first betas that were distributed in a proffesional circle and were not publicly available. I'm really glad it's finally released into the world and I can put my two cents in).
So I sent my two pairs of headphones (HD 650 and Blue Mo-Fi) to dSoniq for calibration profile. And when I got 'em back and heard 'em through Realphones I was blown away by the difference it made. The calibration alone really opened up the sound and made the center image much more defined. I recently compared averaged profile with my custom one and it's very close, not as detalied but very close indeed.
I use it every day when I'm writing music at night in my headphones and as a an additional monitoring option during mixing (especially to get a sense of kick and bass since I don't have a subwoofer). And when i take my headphones off and turn up the monitiors I hear exactly the same thing! Well, not the frequency response of course but the balances, panorama positions and so on. Its exactly the same feeling as sitting in front of pair of monitors in a real room.
I know a few of my colleagues who just don't like it and don't get it. Its fine, different folks different strokes and a matter of taste of couse. But for me it's one of those must have tools in my box. I have it in my Ableton and ProTools templates already set up on the headphones bus. (Btw, if anyone's guessing how to do that - create an effect rack on your master with two chains, put Realphone on one, add External Audio Effect after it and route it to your headphones outputs.).
I haven't compared it to competitor products yet. Mainly because it just works for me and it's already tuned to my headphones. But when I do - I'll remember to update this review accordingly.
Also, I should point out the reason I jumped on Realphones boat is the developer. He's a professional sound engineer and has deep understanding of all the science behind the plugin both theoretical and practical to such an extent that I felt like a total noob talking to him about HRTFs. He's really passionate and invested in this product, constantly listening to feedback and improving it. So if there's something not to your liking in the plug-in - make sure to send some feedback and there's a really high chance it will be added/improved in the future updates.
Realphones turned my cheap SuperLux HD668b headphones into decent monitoring tool.
The sound became cleaner brighter and audio image became more focused. There are a lot of presets and settings, I really liked "Next door" preset because I feel the sound like in another room.
There are many other mix checking options. Mixes made with Realphones translated well to consumer and professional monitor speakers.