Spike

Unlike what Lightthat and Navystylz claim this is not like wow it is SWTOR. Although the ability seems like its similar this does not provide 2 combo points and this one does damage has a different name and costs about 30% of your force bar. For comparison: Cheap Shot. No damage, 33% more cost, a 4 second stun (twice as long and not the same as a knockdown in SWTOR), requires a one handed weapon (since rogues in wow don't use a two handed weapn), no cooldown on Cheap Shot, Provides combo points in wow (SWTOR doesn't have combo points and what is counted as like a combo point is in the IA Ops skill list and STILL isn't really like a combo point).

Basically the only thing that is the same is you have to be stealthed to use this ability like cheap shot and the class is called assassin which isn't like a rogue but sounds like the abilities that wow rogues have. Stop comparing wow to SWTOR. Two different games. Wow was never the benchmark game anyways and doesn't need to start now.

Either way you STILL have to be stealthed to use this, its not designed as a finisher like Lightthat claims. That would mean you would first have to restealth then use this in order to pull it off. Not real convenient. You would be better off hitting them with Assassinate since at least it was designed for that purpose, doesn't require stealth or a facing requirement and hits harder and is half as expensive as JUST a Maul alone not to mention having to stealth then spike then maul which would require anywhere from 55 to 85 force to pull off and two globals. Even if Maul crits AND gets the 30% crit damage bonus from Induction AND the armor penetration from Duplicity Assassinate hits harder, no to mention if Assassinate crits.

Will use 25% damage reduction from armor as an average and 65% surge bonus to crits for this example (general average of players at level 50)
Note: 50% armor reduction does not mean reduces the % armor bonus by 50% due to Diminishing returns from armor (half the armor count does not equal half the damage reduction) or (the less armor you have the more damage reduction the armor provides and the more armor you have the less each point provides)

Assassinate normal hit average: 2900 - 25% armor bonus = ~2175
Maul duplicity hit average: 1865 - (25% armor bonus - 10% from armor pen) = ~1585

Maul Crit with dupicity (at 65% surge) = ~3400
Assassinate crit = ~3590

Got it?
now take that into account along with this abilities cost and you see that using Spike with maul as a finisher is not worth it. Use Assassinate and another Voltic Slash or a thrash or pretty much anything else besides a Spike/Maul combo.

NOTE: to Clarify something EVERYONE that plays an Assassin this is THE ONLY ASSASSIN ability that requires Stealth to use. What does this mean? it means that UNLIKE rogues in wow you most definitely would use this ability FIRST since you should be stealthed on your first attack and Maul can follow since the target is now immobilized (knocked down) and you are behind them or are able to get behind them while they are knocked down. WoW rogues have at least 3-4 stealth openers to choose from, SWTOR assassins have really only 1 that requires stealth and two openers (if the target is at full health - Assassinate would be a good opener if the target is low but then again so would spike/assassinate to make sure the target doesn't retaliate before its dead). Please stop posting false information and look at the abilities at hand.

Not using this first is simply a waste of why you were stealthed to begin with (besides getting the jump on the target)
Note: the previous note is in the terms of PVP. PVE would have different starts and rotations of course, though even a PVE target would be knocked down and vulnerable to a Maul if you still so desired along with the possible chance for Spike to proc a Duplicity and make Maul cheaper. Even more of a reason to use Spike first while stealthed.