I don't know how well the power connector is mounted inside, but I'm kind of loathe to use that connector when the docking connector can do it and I know it's not going to (say) break the motherboard or break off it.

*shrug* Suit yourself. Jim and I haven't had any problems.

The trick is getting it perfectly in the exact/correct place before gluing it, allowing the glue to harden with the player docked, and then making sure it's sturdy and solid there by adding extra glue. In my case, I trimmed the black plastic shroud on the connector so that it was flush against that board to make absolutely sure the glue didn't break loose. (The connector does not penetrate through the board, it rests against it.)

I could see that if your player had a problematic AC adapter jack, or if you used the wrong size connector, or if the connector was crooked or didn't dock cleanly every time, then yes, it could be a problem. But I dock and undock my player from those two docks with that connector multiple times per day, and haven't had a problem with the jack yet.