The Ghurkas are renown for using khurki and they're regarded as some of the finest soldiers in the British Army, so that should say something for their practical use.
As for the cutting, I think JustSomeGuy posted a couple of cutting videos with his khukri in the previous thread, and they did a fairly good job on the pig's feet.
In a combat setting, during Afghanistan a unit of Ghurkas were tasked to kill an enemy commander and bring back his body for identification. They came under fire and were forced to abandon the body, but one enterprising soldier decapitated it first and took the head back for identification (he got in trouble for that).
It's still only essentially a large knife though, primarily intended for all-round utility, and pitting it up against a proper melee weapon (sword, axe, etc) and/or armour (plate, mail, etc) shows up its shortcomings for combat.
Given a one handed spear is primarily used to stab someone in the face, I would say that would stop them effectively.
On a more serious note, to actually stop someone charging requires a better grip, mainly support for the end of the spear (both hands gripping the haft is unlikely to do it unless you've got arms and wrists like a gorilla).
This can be done by either placing the rear hand over the end or by bracing the spear between the ground and your back foot, using your front hand to hold the spear up.
You could theoretically use your body/hip to brace the end, but I don't recommend it as it [redacted] hurts when the force of a charging person in armour is applied at the other end.
In my experience of re-enactment (Norman times), you tend to use your shield to stop chargers - the commonly held view of shields being only being useful defensively doesn't last long after you've been pushed back or smacked in the face by one.