#2 easyHDR - 3-exposure bracketed tiff and/or single image HDR development. Best features: Merge, Lens Correction, Initial Tonality.
#3 Luminar - a Lightroom alternative used as a plug-in to Lightroom. Best features: Looks, B&W Conversion, Erase, Sun Rays, Sky Replacement.
#4 Nik Collection - Once the top-rated editing software (now free). Best features (applied uniquely): Color EFEX Pro (tonality), Silver Efex Pro (B&W), the Dfine (noise reduction). A key powerful tool called Control Point offers direct application of feature enhancement to specific image areas.