Any insight or experience?
TENS unit in labor
I used it with both of my births; while some people find they are only good in the early stages of labor (and some find it annoying), I used mine up till the end and loved it! My husband said the only way he could tell I was having a contraction was that my TENS unit button would be pushed, otherwise I was mostly quiet and still. Between it, my hypnobabies relaxation technique, and just good luck, I had a med-free birth times two. I loved the TENS unit my midwife loaned me for my first birth so much that when I got pregnant the second time (in a different state), I bought a refurbished TENS unit specifically for labor from the UK for something like $60. Worth every penny!
You do have to use it starting in early labor or you won't be able to "catch up" to the sensation, and it is more of a concentration shifter/distractor rather than a "I feel no pain at all" kind of thing, but for me it was a lifesaver.