Good air purifier for dust and allergies?

I have been waking up with stuffy nose almost every morning and i think the dust in my apartment might be the reason. I vacuum and clean pretty regularly but it doesn't seem help much.

I'm finally thinking about getting an air purifier, but there are so many options that it's hard to tell what's actually worth buying.

Right now I'm looking at

• Coway Airmega AP-1512HH,
• Levoit Core 300S,
• Winix 5500-2

If you've used any of them, did you notice a real difference with dust or allergies?