I received my new SC600w IV Plus HI (3 of them). The beam profile is almost identical to the smaller SC64w HI (discontinued light) with one more higher output mode (around 2400 lumens I'd guess --- as of the writing of this, Zebralight has not yet posted outputs for each level.) ZL's website says the beam type is 80 degree spill and 9 degree hot spot. I'd say it's really 80 degree spill and 10 degree hotspot like the SC64w HI. The older SC600w IV HI beam profile, by the way, was/is 80 degree spill and 8 degree hotspot, and I'm pretty sure the smaller SC64w HI was/is 80 degree spill and 10 degree hotspot (both are 2 of the greatest lights ever made to me and my son for the last decade+!!)
The older SC600w IV HI has a tighter and more throwy beam, but it tops out at 1400 lumens (still really great though). Comparing the the highest output of the older SC600w IV HI on max (1400 lum) to the new SC600w IV Plus HI on max (around 2400 lumens), the throw is a similar distance between the two lights since the newer model is a decent amount brighter, plus the overall spill is brighter too on the newer model. Some might like the older model (a little bit more) for the more throwy hotspot with less of a blinding spill (trail hiking/running for instance), and some will like that this new light has a little bit more flood than the older model with admirable throw (similar to the SC64w HI.)
My perception of the additional 1000ish lumens on the newer model is what you would expect. It appears to be around 15-20% brighter to my eyes than the older model (2400ish lumens vs 1400 lumens. So the math on that is: 1000ish extra lumens divided by 1400 lumens = 71% brighter on paper, times the expected 25% perceived difference in increased output = 17.86% perceived increase in output). In other words, increases in light output "appear" to our eyes to be only around 25% of the overall additional output (hope that made sense to new folks, but most reading this already knew all this.)
This new SC600w IV Plus HI is very interesting. I like to use my HI zebras when hiking/walking into the evening, so I can see farther ahead than with a standard flashlight. The older SC600w IV HI punches through the dark a bit further without blinding me with a bright spill, but the hotspot is a bit too tight for closer in. I usually leave my slightly less throwy SC64w HI at home when backpacking since it doesn't throw a beam as far, and I'm already wearing a headlight providing plenty of flood (either an H53w or an H600w Mk IV). This new SC600w IV Plus HI offers more of a distributed beam, and with the higher output, it appears to reach out as far as the older version with sheer power. This new version might be a better option when walking on the beach at night or walking in wide open terrain, so the spill (when on max) doesn't blind you (the spill is quite nice on all levels though once your eyes adjust.) It has good throw but more flood than the older model, so I might not need a headlight on my head while I'm backpacking into the night when using the new model.
For the tint nerds out there (I'm sort of one too), the beam color of the new SC600w IV Plus HI is not great. Out of the 3 I bought, one is a bit greenish, while the other two are an ok white. None of the 3 new lights have the nice warmish looking beam color like the older SC600w IV HI or the SC64w HI (bummer). The tint on these new lights look just like my older SC600w Plus (not HI) if you have one of those.
I'm keeping all 3 lights though. The greenish one is only slightly green, and I'd still use it or hand it off to a friend -- We've had friends and family come to visit us here in the North GA Mountains, and we take them to our favorite sunset spot on top of Mount Yonah. It's baffling to me, but NONE of them EVER think to bring their own flashlight for this hike (1.5 hours up in the daylight and 45 min back down in pitch black). But it's always a whole lot of fun to put an SC64w HI in there hands, and will now be fun to put an SC600w Mk IV HI in their hands for the hike. These lights make good conversation pieces. They also beat the crap out of using a phone light to cover the 2.5ish miles back down in the dark.
My Conclusion - Once again this beam profile (spill and hotspot) looks a whole lot like the SC64w HI but with one more higher output mode. I consider the discontinued SC64w HI to be the BEST all-around flashlight ever made as it offers a good balance for every day use (not too throwy and not too floody). I have considered for years that the older SC600w IV HI is the BEST backpacking/trail running flashlight ever made due to the extra throw with a reasonable amount of spill (all of my other throwy lights don't have enough spill and therefore get left at home most of the time, and all of my floody flashlights get left at home too for the opposite reason though.) This new SC600w IV Plus HI is an EXCELLENT "in-between" model like the SC64w HI always was. One could argue that this new model does what both the older SC600w IV HI does with beam distance and what the SC64w HI does with a combination of throw & flood - a nice marriage of the two lights. Glad I bought them, and I hope this helped you!!
I'm going night hiking up next month, and I will report back on my impressions of this new awesome light from ZL.