Yeah, at less than 400 yards, the TK70 works better than the SR90, as it has almost double the lumens, and a similar reflector size.
After ~ 400 yards or so, the SR90's more focused single emitter, vs the TK70's 3 XML set-up, throws further, and ultimately puts more light down range after ~400 yards.
I did some shots comparing the dedeomed SR90 vs the Dedomed Lambdalight VPT 2....mostly because I found out I needed to focus the VPT's head to get it to throw properly. Once I focused it, the VPT really transformed as far as throw.
These shots were from last night, as it stopped raining long enough to DO some. There WAS a lot of crap/mist in the air though, but, the weather's been SO uncooperative lately, I decide to strike while the iron wasn't AS wet.
I threw in some shots from two small aspherics for comparison, the DEFT edc LR+ (Pocket sized), and the larger Deerelight Aspheric. They too could reach the target tree, and you can see the LED shape preserved on the leaves even at that range. The DEFT is only ~ 80 lumens, IIRC the Deerelight is ~ 300 lumens.
(The round tree and the second Transmission Tower are 405 meters away in these shots, the telephone poles are 87 meters apart...for scale. I adjusted the exposure to make the area lit look like it did by eye that night)
Dark - Control
Deerelight Aspheric
OMG DEFT edc LR+
SR90
VPT
As you can see, the amount of light on that tree, and on the way out to the tree, is pretty nice for both the dedomed SR90 and dedomed VPT. To my eye, now that the VPT is focused to throw, I think the VPT has an edge, at least at this range...in that there's a larger area covered by the light, and its still quite bright at that range.
As the VPT is STILL dimmer on the tree than the SR90 though, I can tell that ultimate range should still be better for the SR90 than for the VPT.
The TK70 (Didn't have it in the truck that night for a comparo shot)...but that same shot other nights was always dimmer on the tree than the SR90 was, albeit the area out on the way to tree was always fully illuminated. This is because that's about the range where the TK70 is starting to run out of lumen juice.
This means the TK70 and the VPT2 are pretty similar in application, in that both produce a great wall of light at fairly long throw distances. It also means that the SR90 can take up where those two leave off on LONGER ranges.