I just got a tens for the first time and am having some success with it. It stops low level pain which is important for me since I get so much of it. Unfortunately it just makes the higher level pain mad. It turns it in to a sort of persistent ache that feels like the regular RSD pain.

I also have to be careful with it because it seems to cause tremors sometimes. I'll report back when I know more but so far this thing is great.

My worst trigger for pain is usage of the affected hand. It doesn't hurt when I use it but 12 to 72 hours later. I've had to learn what I can do and what I can't and it's a continuing education. Using it as much as possible is important but it gets veto power.