Thought this would be an interesting topic. Of course the cost comparison of power vent vs. a chimney is largely going to depend on how long the power vent lasts and the maintenance costs such as replacement parts. Of course the one variable is going to be maintenance performed by the consumer and I'm not sure how I can account for that in this poll.
There is two options, the first set is for those that have had a power vent fail, to define failure would mean it went in the trash. The other is for those that have a power vent and it hasn't failed yet.
If you fixed it to keep it running choose the second option, of course costs to maintain it are open for discussion.
Just a note but specifically for coal applications where the power venter is running 24/7