The stock knife is generally the best one to use out of the bunch, as it has no downsides, and allows you to get those delicious one-hit kill backstabs without worrying about extra traits. The knife of choice for most players unless a situation calls for something different, or one wishes for an alternate playstyle.
+ No downsides, can be applied to many situations.
- See above.Your Eternal Reward
For the Spy that prefers a stealthier playstyle, the Eternal Reward offers an interesting, but challenging way to play. On backstab, this knife automatically and immediately causes the user to disguise as his victim, killing them silently and causing the corpse to disappear, and the death isn’t broadcast on the killfeed. In exchange, however, the user is unable to disguise through normal means, which makes getting that first stab off and dealing with sentries a more difficult process. It can also make things difficult when moving through enemy territory, as you have to carefully pick your targets, as well as what disguises you want to use when you go in to get your actual victim. Enemy players that are stabbed by this can also report to their teammates that you’re disguised as them, negating the silent kill aspect. It is very good for chain stabs, as the enemies won’t be able to hear the normal death cries that come up when a backstab kill normally takes place. Overall an effective knife, but one that requires very careful planning.
+ Silent kills, aids in keeping stealthy.
- Unable to disguise normally, makes sentries more difficult to approach.Conniver’s Kunai
Another knife that offers an alternative playstyle, the Kunai allows the user to absorb health on each backstab, prolonging his own life and enabling him to get out of tough situations more easily. On the downside, it lowers your health a significant amount, dropping it to 60 total. This knife is for those who like the high risk high reward playstyle, as it makes you even more vulnerable in the outset, but gives even more health than you would have had normally when you succeed in getting a pick. Not a knife for everyone, but it does have its share of advantages.
+ Can absorb health of your victim, up to a maximum of 180 health.
- Extremely heavy health penalty makes it difficult to use.Big Earner
The Big Earner has a more unique role that players often underestimate. Much like the L’Etranger, each kill done with this knife (does not have to be a backstab) rewards the user with meter for their cloak, allowing for an additional resource for getting cloak back. This, however, comes at the expense of -25 health. While this isn’t as drastic of a penalty as the Kunai, it still makes you more fragile than you already are. However, the benefits of this knife can overcome the disadvantages for those willing to work with it, as it allows you to quickly regain any meter lost in approaching your target.
+ Gain extra meter on a successful kill.
- Health penalty makes you more susceptible to getting picked off.Spy-cicle
This weapon is a hit or miss depending on how much you fear Pyros. This weapon shares the silent killer trait with the Eternal Reward, instead encasing victims in a block of ice. It also has the added benefit of making the user fire proof for a brief amount of time when hit by flames. However, when the ability is activated in this fashion, the icicle itself melts and becomes unusable for a long period of time. This can be both beneficial and a detriment, as while the effect allows you to escape when faced with a lot of enemy Pyros, the recharge time takes a long while, about 15 seconds, during which you’re pretty much useless to your team. This also proves to be bothersome when dealing with Heavies using the Huo-Long Heatmaker, as the fire ring can melt your weapon before you even get close enough for a backstab unless you carefully time your attack to dodge the flames. If Pyros are being that much of a pain for you, then this “knife” may be useful, but other cases, the loss of the weapon when hit with any fire source can screw you over more times than it can benefit you.
+ Silent kills, can become fireproof briefly to make an escape.
- Loss of the weapon can ruin potential backstab attempts, unable to do anything during recharge.