(Sorry about the long post - I just kept writting and lost track of time/space. I'm sitting here enjoying watching old Outter Limits episodes on the SciFi channel!)
Yeah, I've heard similar comments in other reviews. That is part of the reason I tend to compare my 8099 to my 15TDCL almost in hopes convincing myself that I like the 15TDCL better.
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.
People say the 8099 is bulky. The whole 8099 package at 3.80 oz. is about 1 oz. heaver than the 15TDCL at 2.85 oz. The 8099's boot weights about 1.10 oz and the reference cards weight about 0.40 oz (both weighed with lanyard on, so these are approximate). Ironically the 8099 compass itself weights only 2.35 oz. which is actually less than the 15TDCL.
Ironically the older 8099 weighs in at 3.90 oz, but the newer one weighs in at 3.80 oz. They cut a bit of weight somewhere.
The 8099 is a bit larger.
The 8099's dimensions with the boot are 2.50"x4.00"x3.85". The 15TDCL's dimensions are 2.375"x3.875"x0.50".
So, the 8099 is 5% wider, 3% longer, and 25% thicker than the 15TDCL.
The boot & cards do need to be slid up the lanyard in order to use the compass on top of a map (though not to orient the map), but it can easily be used to take bearings at belt (or chest) level with the boot on. Since I tend to mostly use the compass for orienting the map and taking bearings the boot isn't an issue for me.
The mirror on the 8099 (1.25"x2") is indeed smaller than that of the 15TDCL (2.38"x2.56") - which might account for the heavier weight of the 15TDCL compass itself. Still, I find sighting bearings with the mirror on the 8099 much easier than with the 15TDCL - possibly because or the circle-in-circle method. The larger mirror on the 15TDCL would certainly be better for signalling, but I carry a separate signal mirror in my kit.
There is bit of wiggle in the cover joints on my older 8099, though I hadn't noticed it before. They must have changed tolerances, because on the newer 8099 the main cover is rock solid. The smaller mirror cover still has a bit of wiggle at 90 & 45 degrees, but is rock solid when fully open at 180 degrees and when nearly closed. Like I said, I've never noticed the wiggle before and it has never bothered me.
As mentioned, the 8099 dial shows two numbers - green numbers for forward bearings and black numbers for backbearings. On my first 8099 the green numbers are toward the center and have lower contrast, but on the newer one the green numbers are on the ouside of the dial and are much higher contrast due to a bolder font. I like the numbers on the newer one much better - very easy to read, at least for me. 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.
I like that the 8099's declination can be adjusted without a screwdriver. That is how all the Brunton-designed compasses work, and I haven't had any probllems with any of them that I've used (8099, 8096, 8010G, 9020G). 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.
The settling time on each seems pretty similar. Because of the nature of the 8099's disk there isn't any "wiggling" that I see on the 15TDCL, but the wiggling never bothered me. 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.
I can't tell what the dial markings are printed on - could be cardboard. I can't tell since it is embedded under plastic so nothing can touch them or wear them out and I don't care to rip mine apart to find out. The markings are printed on white, but on the newer 8099 it is actually brighter white than on the older one. I suppose this is part of the better contrast mentioned earlier. 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.
By the way, the reference cards are printed on durable plastic. They include:
1. A quick clinometer scale that is displayed under the compass capsule when the boot is on.
2. First aid instructions for choking, fractures, heatstroke, hypothermia, abdominal wounds, frostbite, snake bite, clearing airway & mouth-to-mouth breathing, cardiac message (supposed to be massage?), shock, bleeding, and burns.
3. Instructions for sighting a field bearing, traveling a bearing, and orienting a map to true north, getting a map bearing, and triangulation.
4. Survival hints: if lost, signals, water, water purification, food, shelter, common knots,
5. Instructions for clinometer measurement: 1 degree resolution using dial
6. Tangent conversion table for calculating heights, common metric conversions
7. Instructions for UTM grid determination
8. Instructions for height measurement
9. UTM corner tools for 1:24k, 1:25k, 1:62.5k, 1:50k, 1:250k, and scales for 1:63.36k, 1:62.5k, 1:100k, 1:50k, 1:250k, and 1:25k
The survival hints say to move as little as possible to maintain strength, make shelter & signals, inventory supplies & ration food/water, travel only if you know where you're going, and don't panic. Keep at least one fire going, use three of anything to signal. Water is important - conserve and try to find more, but don't ration in hot weather. Drink what you need and conserve fluids by seeking shade, and moving only as needed. Water purification methods listed are boiling water for 20 mins, bleach, and iodone. Keep shelter as small as possible so body heat keeps it warm. Choose a location to protect from wind, rain, snow. Knots shown are the taughtline hitch and the square knot.
There markings on the bottom of the 8099 are only printed on - with no engraving. Those on the 15TDCL are engraved and printed. I've read others have a problem with the markings on the 8099 coming off. Since I mostly use the compass with the boot on that hasn't been an issue at all for me. 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. Hmmm.
I haven't used the meridian lines on a compass since I was a kid using a compass that didn't have adjustable declination. 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). 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.
I do wish the 8099 had a UTM corner tool right on the baseplate instead of on the reference card, but I tend to use a UTM grid from maptools.com instead anyway.
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.
Like I said, I just find the 8099 to perform better for my uses (orienting the map and sighting bearings). While I have too many compasses, I prefer to use the 8099.
I find the Silva 54LU very intriquing, but lack of adjustable declination makes it unacceptable for my needs.
Ken