A lot of people like the Otis and apparently some military personnel buy them.
The disadvantage is the same for any pull-through device.
They WILL break off and leave the bore blocked with no way to get it out unless you have a rod.
Most pull-throughs fail when the cord breaks, the Otis fails when the cleaning brush or patch holder itself breaks.
And they DO break sometimes as some users have reported.
As long as you inspect it very carefully and replace any worn, damaged, or suspect parts it should be good to go.