"I did get a bubble in my first 8099, but they fixed it for free and since then neither of my two 8099's have gotten bubbles."

The bubble issue with Eclipse compasses has been mentioned many times by many people who bought Eclipse model compasses. Sometimes the bubbles disappear when the compass is warmed, sometimes not. I can't quantify the exact number of complaints or what Brunton may or may not have done to address the problem (they don't mention it), but I do know that since its introduction, I have seen many more complaints with the Eclipse capsule than with other liquid-filled compasses of similar price and class (including other Brunton models).

"So, the 8099 is 5% wider, 3% longer, and 25% thicker than the 15TDCL."

Measurements aside, the 8099 is just plain bulky for what it does - even the lanyard is oversized. I can fit most Ranger compasses into a shirt pocket, but not the 8099.

"I also like that the 8099 displays one tick for each degree - the 15TDCL only displays one tick for every other degree - this is probably made possible by the 8099's magnified reading area which works well."

Well, the eye splits 2-degree increments easily, so actually the 8099 isn't any more theoretically accurate than the Ranger designs - both are readable to one degree. Someone who demands higher accuracy would probably switch to a Brunton Transit or a Suunto KB sighting compass, but you certainly won't get more accuracy out of an 8099 than say a MC-2G or a Silva 25 Ranger, especially in dim light.

"I've always figured that settling time is a balance between convenience and accuracy, and a compass that settles too fast might not settle off the true bearing a bit."

Actually, that's not true. Fast-settling handheld compasses with 0.25 degree accuracy are available now, but they are expensive, do not possess a separate baseplate, and usually need to be rested or tripod-mounted to achieve their inherent accuracy. Another method is to use two magnetized needle ends, which gives a very fast and accurate needle. Orienteering compasses such as the Silva Jet or Suunto Arrow have them, though such compasses do not normally feature sighting mechanisms due to the specialized nature of that sport. The global needle used by Suunto is a twin-pivot design that settles very fast. Suunto and Recta (owned by Suunto now) have since combined that design with a prismatic sight that is also very accurate. In contrast, I think the Brunton card-type needle ('circle-on-circle') design offers nothing in the way of an improvement. At the very least, it needs a heavier dampening fluid.

"The white numbers on the 15TDCL's dial is printed on the outside and under magnification doesn't appear to be engraved. It definitely is touched by the operator. I see some of the edges of numbers chipped and missing, but there isn't enough wear to make it unusable."

The 15TDCL is one of the lower price-point Ranger compass models. At some point, something has to give. Try the 25TDCL or 25TDCLE, or Suunto's MC-2G, all of which have either raised or engraved dial markings, as well as engraved scales and markings on the baseplate. They also feature a raised transparent gripping section, so the fingers never touch the printed portion of the dial.

"I've wondered if the ink removal on the 8099's are related to DEET. I've rubbed and rubbed on mine - even scraped it for a while using my fingernail and don't see any wear."

No, it's because the numbers are only printed on. If you have an 8099 and always keep the rubber boot on, (and never use the compass as protractor or measuring tool on the map), yours might last longer. It's almost standard practice for 8097 and 8096 compass users these days to place clear packing tape on the baseplate bottom to preserve what's left of the roamer scales and markings.

"I like that the 8099's declination can be adjusted without a screwdriver. That is how all the Brunton-designed compasses work..On the 15TDCL (and the Suunto M3) I worry that I might strip the adjustment screw, but have assumed (hoped) that the supplied aluminum tool is not as hard as the screw head"

It's a matter of personal preference. I have never had any stripped adjustment screws on Silva or Suunto compasses (of course, one rarely needs to make that adjustment more than once prior to a trip), but I HAVE had too many Bruntons slip their declination setting. The Brunton adjustment system necessarily changes the relation of the dial to the capsule bottom, forcing the designers to place the orienting lines on the outside of the non-transparent dial (if they put the lines on the bottom of the capsule, one would have to remember to readjust declination to zero and back again each time you took a map bearing). To me, the Brunton declination system takes a definite second, as the whole point of a baseplate compass with adjustable declination is to rapidly coordinate with map, including ease of use as a protractor to measure one's true bearing along a planned course.

"To make up for that we'd draw magnetic N/S lines on the map and use those lines to set the bearing (without having to orient the map to north).

I have never been a fan of drawing magnetic lines all over a map myself. As you imply, few people do it anymore. You sometimes see adventure racers still employing the practice, always done in advance, usually with drafting boards and one-arm protractors to accurately reproduce angles on special large-scale racing maps. Otherwise, it is rarely accomplished with complete accuracy (using the declination diagram as a angle indicator is a common mistake) and the pencil lines often obscure important detail. Also, having bought a compass with adjustable declination, it seems pointless, now that the compass can be easily adjusted to give true bearings and make compass and map 'talk the same language'.

"These days I just orient the map and "box the needle" since UTM grid lines aren't truely N/S and I prefer not to draw true N/S lines."

You never take a map bearing along a planned course on the map, point to point? I find it indispensable, especially when the initial landmarks on my course aren't readily distinguishable from each other. To use a compass as a protractor with a USGS topo map, you can orient the compass' meridian lines with the map margin or the intermediate lines/crosses of longitude, which on US maps corresponds to true north. That's one of the major benefits of a baseplate compass.

"One other thing to note is that the 15TDCL has glow-in-the-dark points while the 8099 doesn't. That hasn't been a problem for me since I don't navigate with a compass in the dark."

Most people don't navigate with a compass in the dark, but occasionally an emergency or other circumstances (hunting, etc.) require its use in the dark or - in low light. The 8099's small mirror and complete lack of luminosity or built-in illumination genuinely handicap it in that respect.