I signed my pact with Satan a little over a year ago and I can tell you that I feel amazing.
This may seem childish, but for my entire life, I felt like I was being stalked. (mostly during the night) When I slept, I always felt like someone was staring at me, ready to grab my feet and drag me out of the room. When I was alone in the house, I would feel a chill in random parts of the house, and felt eyes staring at me from a corner of the rooms. I have even heard my name whispered to me once or twice during the night. All of this stopped immediately after my dedication, even to this day.
For magick, in my experience, yes. Every spell I have EVER used has worked. I had two bullies in freshman year of highschool who always tormented me (I was an anti-social child) and I casts a spell on them to make them "leave my life". The first one actually moved two weeks later, and the other one stopped bullying me and actually seemed to forget who I was. Another spell I cast was actually WAY before Satanism. I read the book "The Secret" which has the similiar fundamentals to magick. At that time, I wanted an Xbox 360 (they were really popular at that time and I was 10) two months later, it was bought for me for no reason. (this might have been because I asked my parents for it SO often, but I'll put it out there just for debate) Another spell was for this girl whom I liked alot, but I was too shy to talk to her, so I cast a spell to make her want to kiss me... I regret this spell, because it happened in about 3 weeks. She was "dating me" for 5 days. But then I figured out she was cheating on another man for me. So I now avoid spells like that, because of that possible risk.
Please know that Satanism is NOT about nazism. Nazism is an idealogy that is completely seperate from Satanism. Some Satanists are nazists, because of historical atrocities. They think that Jews are the reason for Satan being so torn apart from humanity. But I have never heard of any Satanist actually hating on Jews, just for being Jewish. I think they are actually just hateful towards the religion, not the people.
And don't be afraid of the rituals or Demons. I have performed a couple and there is no blood-letting (except for the dedicaton, but the blood for that isn't a requirement, it's a formality), no sacrifices of flesh. There may be offerings of food or wine, but that's just for being polite and respectful for any Demon's help. Similiarly to paying a musician who plays for no pay on the streets. You may enjoy their music and you want to pay him for his music, because you are thankful.
I could go on and on about why you should be a Satanist or atleast spiritual, but I want you to study this for yourself. Don't take the word of others, because they will tell you what they believe. Test your curiosities for yourself. But do know that I BELIEVE that Satan and his Demons are completely benevolent and are merely victims of bad luck and lies.