I posted a brief article on the differences between 'out of the box' renders of an HDR scene with NIK Softwares HDR EFEX PRO and Photomatix using some shots of my bathroom... can't find the original post now... but here is a quick 'Bathroom' comparison of an HDR EFEX PRO 2 shot and Photomatix shot side by side.
I used an un-scientific 60 second editing rule on each shot... i.e. I didn't fiddle with the default output much before posting.
You can see that the NIK Software HDR Efex Pro 2 software has created a more realistic image by default that doesn't have that HDR 'look'. While some people like the effect I prefer the more natural appearance of the NIK render but this will be a matter of opinion.
NIK Software HDR Efex Pro 2 features a number of presets that provide a baseline for further modifications and some of these pre-sets can have a very strong effect that works better in some situations.