As neat as the D4 is, the D1 is quite useful.
I got the neutral HI D1 first, then ordered a cool HI D4 to go with it.
The D1 with 1/4 the potential lumens and battery drain of the D4, but with good throw, and it's still quite a small light even with the 18650 tube, with an 18350 tube it's comically small and head heavy, and even more impressive of a thrower for its Liliputian appearance.
D4 with an 18650 tube and D1 with an 18350 tube are quite a little pair... but if you don't actually need either one that small, definitely go 18650 for both.
If I could only have one I'd definitely have the D1, really practical light.
I particularly appreciate how both lights have a very non aggressive look to their design, they look like toy lights, it complements their over sized power and lumens range.
I've managed to drop my D1 now onto concrete almost every night since I received it btw, I sit in the dark on my porch, put the light in my lap, forget about it and stand up. So it's survived 15-30, 2-3 foot drops already, doesn't seem to make any difference.
I did put a little bike inner tube on each end in anticipation of a hard life, and I'm hoping that we eventually see an "Indestructible" version of these lights with some nice moulded rubber bumpers pre-installed, leaving plenty of exposed aluminum for heat transfer of course.
