Very dangerous. both for the user and the person attacked.
For the person attacked, IRL, the electricity would cause the muscles to flex, basically immobilizing the person. After the first discharge, they would be disorientated, all their muscles twitching, and basically unable to offer an effective defense against a second attack.
For the attacker, IRL, this weapon is extremely dangerous AFTER the first hit. Electricity always follows the path of least resistance, and once you introduce a liquid medium (in this case the victim's blood!! all over the blade...), that path becomes unpredictable.... and any insulation protecting the user, could fail, thus ending up shocking them!
**Note, the current in the blade would not be large enough to cauterize the wound, as the Amperage would not be able to be made large enough and portable enough to make an effective use weapon. (you need around 3 to 5.25 amps to cause instant cauterization within a combat pass [1 sec]. At which point, the cauterization is really just a secondary effect of a case of terminal Death.) Generating that much instant amperage on a constant basis is possible, but not really portable. to get your 10 charges or so, you would need something the size of a car battery.
remember, cauterization and surface burns are two different things!