EZBlocker is designed to be the simplest and most stable ad blocking application for Spotify. EZBlocker uses a blocklist, so you can choose which ads get blocked. You will not notice any performance changes to Spotify. When you want to listen to songs, just load up EZBlocker and you'll be on your way to listening to advertisement-free music.
In addition, EZBlocker is fully open source, which means anyone can see the code. EZBlocker is free of any viruses and is guaranteed not to slow down your computer.