I am a bit of an NVIDIA fanboy when it comes to GPUs. This is partly down to being a long time Linux Desktop user (until recently) and them having excellent drivers allowing me to pretty effortlessly get proper hardware acceleration working.
In my lab environment I have an old Nvidia Quadro P400 that’s set up for various transcoding workloads and its been working absolutely great for me despite being an older card. I have been primarily using the h264 codec but I recently moved over to h265 (hevc) mostly out of curiosity, and to see if I could get quality on-par with h264, whilst getting similar file sizes.