How much of an improvement?

I've been using a 820 dongle for a couple of years now and was wondering how much of an improvement the Airspy or SDRplay are over the dongles?



I'm intrigued by the SDRplay now that it's half due to it's ability do HF.

What exactly would I be missing by having the 380 to 430mhz gap in the SDRplay?

How much of an improvement?