I don't own a pair myself due to their cost, but I've known a few people who swear by them.

You bring up a great point that I think the article left out—scheduling the tasks ahead of time before the day you have to do them can help tremendously. For me, that is motivation in and of itself that I can just start the next day with it already planned.

Do you ever find yourself avoiding to add sub tasks because you simply don't want to do that thing you've been putting off?

No, because, (and this is the trick for me) adding tasks and subtasks and planning is a completely separate activity and headspace. When I am doing that, I am in planning mode and I don't imagine how much it will suck to do a task. Just plan.

Then when I do, I just do.

This planning and review phase you describe is the first step in a GTD workflow.