I don't know about "best", just my personal preferences. I use a Roku Stick to stream to my tv (I don't really like watching on the smaller screen of a phone or my pc). I currently subscribe to CrunchyRoll. Funimation & Netflix. I used to subscribe to Hulu and may again depending on how things play out this year between Hulu, CR & Funi. I'll also occasionally use a site called TubiTV which has a selection of older series, some of which aren't found elsewhere (for example I used it to watch Accel World earlier this year). It's a legal streaming service that has a variety of content (not just anime). It uses ads instead of paid subscriptions, but most of it's content is older and not the best video/audio quality.
I also have a significant collection of anime dvds I've accumulated over the past 25 years. While I don't buy nearly as many as I did before streaming, I still like to have a physical copy of titles I really enjoyed, not only to help support the industry but also you never know when I title might get taken down from a service & there have even been instances where they were edited/censored after the fact.
Also. my personal preference is for the original language dialogue with subtitles, but there are a few titles out there I actually consider the dub to be as good or even better than the original.