It would be easier to provide a precise answer if you named at least the key functions you want to view in your software. Also, it's hard to select only one best facial recognition software because there are many of them in the market.
So, let's present at least the top 5 free softwares in the market worth our attention, including Ageitgey/face_recognition, CompreFace, FaceNet, DeepFace, and InsightFace-REST. However, they're the free versions, and you should consider some nuances. For instance, some of them, including Ageitgey/face_recognition and FaceNet, don't provide REST API, while Deepface and InsightFace are actively updating, aiming to provide only convenient and easily scalable REST API.
Apart from the open-source versions, it's good to mention 5 popular paid software, including Amazon Rekognition, Deep Vision AI, FaceFirst, Face++, and FaceX. These softwares are similar in their services but differ in their pricing plans. Most of these tools offer services from emotion recognition, landmark detection, age estimation, and gender recognition. But if you're interested in their cost, you can find the actual info on their site.