If you mean that I was impressed when I watched it, then I guess it's Sp3c7er's or however it's written, and Achire's. But that's also because when I watched Sp3c7er's one I was a complete noob and watched in awe at how he RHAd Banshees to death while the only thing I could do was run around the battlefield screaming in fear of them.
Judging with the experience I have now, and by today's standards... That solo is far from being impressive.
Take a look at how long his shields take to recharge.
See how quickly the enemies lock on to his character model when he's out in the open.
No geth scanner used.
No cyclonic used.
Take a measure of just how aware he really is.
Using hipfire instead of ADS so he can DPS whilst having perfect vision of flanking avenues.
Weaving with the pizza to minimise exposure time to prevent ravager lock on; at lower frame rates you could just wing it as the shots will miss from that distance - if the ravager can even get a lock at all.
There are parts of his solo which are played far too cautiously and it actually costs him as a consequence; going on the aggressive could have saved him time and consumables but that's the benefit of spectating afterwards.
Seen as how Spectre is one of only two people I know of who's solo'd platinum at 120+ with no shield boosting gear and no wallhack, I'd say its still a pretty damn impressive display - not a week after the difficulty was released, when you consider just how many subtle fps incurred changes have an affect on gameplay.
Running around immune to bullets 80% of the time as a novaguard @60fps just doesn't stack up. You can nova cancel your way through anything with just a little timing.
With enemies reacting in less than half the time than they do at 60fps, Spectre's solo remains the most impressive solo we've ever seen. His time is not impressive, his play style and metagame are, however.