I used to play on ESEA and MM depending on my form for the day. After the rank change I've been sitting at MG2 for a bit (From DMG/LE)and have been slowly moving back up. ESEA is great if you want to pay for a service that's 128 tick and has competent players. But I wouldn't recommend it unless you've at least been DMG and even then I'd rather you be an LE if you're going to subscribe, you'll just get flamed if you aren't good enough.
Other than that I'd stick to MM, FaceIT is okay but I've never really focused on playing ONLY on FaceIT