Product review (4 stars): All that is useful was the 4" brush and the rods
My vent was almost 40' long and though the basement is finished there was an elbow in the vent visible 24' from the outside in a storage room.  Luckily I was able to get the first 24' from the outside and then the next 16' from the elbow I removed.  It worked very well.  It went around multiple bends without a problem.  It did not seem to want to go down the vent from the dryer end for some reason.  I didn't want to force it.  Coming from the other direction was no issue.

Would have given it 5 stars if it weren't so over priced.  I bought this kit plus the 12 foot extension kit.  All that is useful was the 4" brush and the rods, the rest I found no need for.  So I got 8 3' threaded rods and a 4" brush for $60.  But the product worked so maybe I shouldn't complain.

The directions say put tape where the rods screw together.  Not really sure how much that would help if you got into some thick lint and put the drill in reverse.  Understand that if you put the drill in reverse in any situation this thing is going to come apart and you'll have a huge problem if it is a long vent.  Check and double check each time would be my advice.  Better advice might be to put electrical tape on the drill so you can't put it in reverse.