Laser and electro are about as permanent as each other at this point.
The Rubies, which can barely be found anymore were not, thus the old, laser is not permanent line. The rubies reduced hair, but it always came back.
The Alexandrites and YAGs are permanent, but you have to keep going for a year/year and a half. You need dark hair for it to work well though.
If you have a choice between laser and electro, ALWAYS CHOOSE LASER. Its faster, better for your skin, and is significantly cheaper in the long run.