My vacuum doesn't suck

I wish that were a good thing. But really, a vacuum is the one thing that's supposed to suck and mine barely does. I was looking at different vacuums at the store today and was happy to see that there were a lot that we might be able to afford. But I don't want to jump right in and buy one just because it's cheap. If I do that I'll likely get a vacuum that doesn't suck again. I'm going to have to research all kinds of vacuums, like Miele vacuums, before I choose one.