I have used the LP 3mm. I think you are correct in that it is the same as the Orion Edge-on, but lots cheaper!
It is a nice eyepiece, and sharp to the edge even in an f5 scope. Great eye-relief. It does show a bit of reflection from bright objects just out of the field, like the moon and Jupiter, and it doesn't offer quite as bright an image as the TV 3-6 zoom operating at 3mm- but it is hard to pick much difference. (A slight difference in colour too.)
However, for the price I don't think you can go wrong - and it doesn't rattle!
All the best,
Dean