I use avconv, which is a tool for running stuff through libav. It's free, very fast, and extremely powerful.
My brother prefers MediaCoder, which is basically a Chinese (they have an English version tho) frontend for libav/ffmpeg. It supports OpenCL and CUDA and other nifty things, but I found it to be horribly unreliable.
i7-4790K (NH-C14), 4x8GB DDR3-1866 CL9, GA-Z97MX-GAMING 5, SAPPHIRE TRI-X OC 290X, 2x 256GB Q Series / 128GB Vertex 4 / 3x3TB DT01ACA, CX750M (PSU), VG248QE, 3x M2060SWD2, MIMO 720F, Majestouch-2 (red) / Vengeance M95