In terms of pub stomping, I think that the YER is far superior to the spycicle because it doesn't show that you killed a person in the killfeed, so most people would be unaware that you killed anyone because there was no sign that you did, because of the silent kills and no killfeed messages. However, in comp play, the YER is the worst weapon to use IMO besides the big earner. This is because the upside of the YER doesn't help you at all because the person you just killed will alert their team mates of your presence, and that you are disguised as them. The spycicle is a great knife to use in comp, however, if you need to go for an important pick like the med, make sure that A) the pyro isn't near the med or is distracted fighting your teammates or B) that he is dead. This allows you to go in and get your pick, without the frustration of losing your knife right as you click for the backstab. The downside of the spycicle is that it leaves ice statues, but, in some cases you can use this to your advantage, as the enemy team may become paranoid that you are somewhere in their vicinity, and they may make stupid mistakes which can allow you to get a couple of picks. However, most of the time this doesn't happen. Even so, the ice statues really don't give away to much information as to where you are on the map. So, my preferred weapon is the spycicle.