I have both the SDRplay RSPdx and the Discovery HF+. In spite of claims that the Discovery is more sensitive, in the real world they perform about equally. The RSPdx has the advantage in terms of multiple antenna ports including one with a bias T, which I use to power my amplified MLA-30 loop when I use that in my high noise environment, as well as full range from VLF to 2 GHz, built-in filters, and online community for support when learning (if you need that). The HF+ is very compact and I think is a bit better when it comes to handling front end overload, however I still use inline bandblocking filters because I'm in a major city with tons of AM and FM broadcast signals, and I sit in the middle of a triangle of AM broadcast towers. Something to consider depending on the exact nature and location of your QTH.