Black glass / clean glass is a love hate relationship, your trying to cater to different people at the same time.
To the clean glass people, a fire needs to burn at a certain temp, with a certain moisture percentage of the fuel, with different fuels (wood) at different moisture percentages that are found around the county its almost nearly impossible to find the right burn at low (smolder) and still keep the glass clean. I personally think that the ashford stoves come the closest in this respect (stove design) but its something that will imo will never get truly nailed down, without sacrifice.
But don't trade a little bit of dirty glass for function, I came from a high output air tube stove, I burnt 6-7 cords a year, was baked out of my living room, had to reload 4-5 times a day and had other less than desirable issues, I bought a princess and that all went away (dropped to 4 cords on a hard winter), and I don't clean my glass and I'm able to keep the glass fairly clean when running on medium to high settings.
Black glass people - Doesn't it feel good to load once +24hrs during the season and just see a little tiny glow in the box, then when it gets really cold burn some more maybe load twice a day and have a decently clean glass with candle flames, but know at the same time we're burning more wood than we would like because we got use to black glass = long burns, low usage = warm house.