A chimney sweep brush vs chimney cleaning logs. I get this question frequently. I cannot speak for the cleaning logs because I have not observed their effect over time, with various degrees of creosote build up. I have been cleaning chimneys for 24 years now. To be able to answer this question, I would have to start with a CLEAN chimney. I would have to record how much wood was used and how long it took for the chimney to get to the point where a manual sweeping was required. And of course, I would need to keep a record of when the chimney cleaning logs were used. My best advice (if you are going to use these logs) is that you start with photographs of your chimney flue and the smoke chamber above the damper. Record all of the data I listed above and come to your own conclusion. Make sure you have a reliable chimney sweep if you are going to use his assistance. The logs do not take the place of structural and mechanical inspections. These need to be done as well. And remember, there are simply situations where cleaning logs do not take the place of chimney sweep brushes.
Have a good week!