I've only tried Akvis Noisebuster at the moment, witch gives better results than octane hotpixel's filter.
(just desactivate it before sending image to Noise buster).
If I find some free time, I'll do test with these but if somebody have some comparsions, you're welcome :
-Photoshop median filter with multiple renders at low samples.
-Imagenomic -> Noiseware
-Topaz labs -> Denoise