Bisectplus

Bisectplus offers all the features of bisect, plus the ability to more easy and precise make a cut, by setting up a plane-object to make the bisection.
While the basic bisect function offers a gizmo, Bisectplus uses a plane-object that can be picked in the 3D-View with an Eyedropper.

In the user interface you will always see the selected target at the top, such as to be sure you use the function on the right object. It's also possible to change the target by just selecting another object (non mesh objects, will hide the user interface though, as they can't be bisected). 

With the target selected and the plane chosen, it's time to consider if you want the bisection to happen on the entire mesh of the target or if you have a selection you want it to be limited on.

The option to "Remember the manual selection" will re-select the selection you had after the operation is finished, it's on by default.

The option to "Override the selection" can be used simultaneous as it only ensures that the operation will happen on the entire mesh. It's off by default.

Further options like Fill, Clear Inner and Clear Outer as well as the option to adjust the Axis Threshold, are the bisect basic functionality to allow destructive operations.

While Fill closes the cut, it's use is only really advised if either Clear Inner or Clear Outer is also selected. The Axis Threshold on the other hand is only available to eventually fine tune the margin, with which the bisection and the finishing operation of my add-on decides close/far the vertices of the object can be to be considered on either side of the cutting-plane.

After the bisection is done, the target-object will have up to 3 vertex groups generated to reflect the bisectionloop (the vertices along the surface of the cutting-plane) and both or one side of the target-object from the plane-object.

In case that nothing is selected and the "Override selection" option is not used, there will be no cut, but the separation in Front and Back based on the plane-object will still be done and the vertex groups generated.

UPDATE:
Little fix concerning cancel(l)ed operations.

The add-on is free, please do not pay if it's not convenient for you.
You can also find the add-on on https://github.com/Xylvier/Bisectplus/wiki.