I'm considering to buy a compressor or a tank..

Well it does help to look at what day this is? April 1st. And some shooters always want the latest and greatest so here it is......................

As for your question about the tank or compressor. I cant see using just a compressor unless you only needed filling your rifles while at home. If you have both you can fill the tank and then travel with your guns. I go to friends houses at times and just take my tank with me.