update:
well i have 2 of the bottle stoves now & have used them extensively, mostly with vargo triad or trangia alcohol stoves, a few times with twigs which of course creates a lot of soot, but they perform well with both methods, haven't used directly in fire with hot coals yet, but there is always that option eh...
one of the stoves is dedicated to a condor water bottle pouch mess kit nested with kleen kanteen 40oz. & pathfinder stainless cup & lid, the other is a backup i keep with my base camp kitchen kit... they have refined the pathfinder cup, no more sharp edges, still not as perfect a fit as the olicamp stainless space saver mug, but it has several advantages including greater capacity, the predrilled holes for spreader hook, & newly included lid which has really slick design features i won't get into here since we're talking about stove...
the only issue, can't really call it a problem since it doesn't seem to affect performance as much as anticipated, is that there is a lot of steel material at the top of this stove, which collects a lot of heat & turns bright orange, especially over the hot blue flame of alcohol stove, not so much with twigs since flame isn't as directed, but anyway that super heating of the metal there could possibly cause warping over time, but it doesn't seem to deflect so much heat as to reduce efficiency & boil times significantly as far as i can tell...
for the condor pouch kit i have also added the pathfinder pack stove ring to share duties with the bottle stove, the stove ring is a perfect size pot stand for the vargo triad & increases direct flame contact on bottom of cup or canteen, the ring fits well in pouch over top of kanteen, so i can have many options for single or multiple container boiling/cooking with this setup...
the bottle stove is versatile in that it is of course the perfect size for the cup or stainless water bottle, the solid construction & wide base means it's also a sturdy stand for larger diameter pots or pans... while it's not a fancy gasifying twig stove, it definitely serves it's purpose as a lightweight & compact twig stove, fire cooker, & pot stand for alcohol stove that nests perfectly with right size cups & bottles, i mean if you're gonna be carrying a bottle & cup that size why not have the bottle stove? doesn't make as much sense if you don't have the cup & bottle i guess eh...
holds it's own against vargo hexagon or emberlit twig stoves as well, smaller yes, but the aforementioned benefits of weight & nesting makes up for it's size, & anyways it's purpose for me is more of light use like day hikes or backpacking, smaller boiling/cooking tasks around camp, or emergency use with the condor pouch mess kit...
wouldn't want to use this as my only stove for an extended time, but still really like it for what it is, & both of mine are holding up well to use in the field