My understanding of J-Tube versus a PEG is as follows:

If you already have stomach problems  such as acid reflex of food coming back and causing burning sensation or other stomach related problems, then the doctor may decide to go for J-Tube instead of PEG.  If you do not have such stomach problems, then PEG is much better and much easy to maintain.  PEG operation is much simpler and takes only 10 to 15 minutes.  It can be done using Pull method or Push Method.

https://www.youtube.com/watch?v=YjkZ6mQJ4JU

Actual video of a PEG operation

PEG cleaning Method

J tube operation is a more complicated.  J Tube is inserted into the opening of the small intestine and bypasses the stomach. Keeping the J-Tube in place inside the small intestine with clip is tricky and the clip may slip off causing problems.

https://www.youtube.com/watch?v=llQxfVFnLLA