well J, not long after i made this thread i ordered the PT Corona to find out myself. all i can say is enjoy it. i think it's the best headlamp that's been made.
the flood is so nice. it illuminates trails like they're hallways. even on the single LED in low mode, it still provides a nice flood to walk by.
the circuits are as strong as any other light i've owned. i've tossed it in my pack with all my other lights to take them out and shine them around. i've whacked my head on low branches while making new trails. and a friend of mine fell while she was wearing it and slid down a hill, dragging the battery pack under her head the whole way down, haha. everything's fine.
the only things i can think of that are remotely wrong with the Corona:
#1) the cable gets stiff in very cold weather. this is true to all lights i've seen with battery packs connected with cables. so can't take points away for this.
#2) the light's vertical adjustment is one smooth movement on a tight joint, rather than the usual click'n'stick most headlamps use. when i was using the headlamp to shovel during 20 inches of snowfall we got a few days ago, i noticed as the joint got cold and wet it became too easily susceptible to shocks, and when throwing big shovel-fulls of snow the light would rotate all the way down and blind me! luckily this minor issue is fixable. the joint can be fine tuned with a phillips head screwdriver and a small gripping tool (pliers or whatever you prefer) to hold the nut on the other side of the hinge. so, again, can't take any points away there.
#3) the tab that secures the battery pack closed is connected by a hinge and seems kinda cheap. it snaps onto the hinge rather loosely, and on my personal Corona, the snap on the tab has already chipped in one place (does not effect the tab's closure/security or battery pack's waterproofness). it's an easily replaceable part, and i'd imagine PT would send a replacement, no questions asked, if it should happen to be damaged, or one wanted to carry a spare or two on hikes and camping. personally, i find this to be my only REAL knock on the light. i wish there were a more secure tab available to close the battery pack. something that secured it shut more tightly and more solidly. but yet again, i can't really take any points off for this either, as it has held up without failure to several falls onto hard-packed slush/snow and several bumps into tree limbs (and a doorknob once, but don't ask).
i very highly reccomend this headlamp. the heatsink is absolute genius. the buttons are very easily operated even with semi-thick leather gloves. actually, as i'm listing pluses i thought of another minus. all of the LED's on my particular headlamp are remarkably white. except one. and yeah, it happens to be the very bottom LED that comes on in 1 LED mode. *sigh* haha, once again, can't take any points off for this. it's the nature of the beast. but quite a violet colored beast with a big artifact thru the beam. haha.
but back to pluses. it's very comfortable to wear for, well, up to 4 hours, which is the longest i've worn it so far. it is my first headlamp with a top-strap that i've found comfortable for some reason, and it's surprisingly lightweight with lithium AA's.
it works very well in foul weather including rain and blizzard-condition snowfall.
the light it puts out is absolutely beautiful. when hiking i most often use it on low-power with 8 LED's. well, so far @ least, 'cause i've mostly used it for shovelling snow and yielding a 15" khukri to whack a couple new trails thru the forest. i did take it along for a hike with a couple lady friends who preferred navigating the trails by the bright moonlight that was shining that night, and i ended up using it on low mode with 1 LED (i'll be damned if i'm going to hike and not play with any lights!), and it worked just fine with the nice flood pattern. it really does seem to light up BEHIND your field of vision. it's great.