My legitimate favorites are Type V3 and Glenn Webb, and by that I mean they're the only ones I watch. V3 gives really concise yet thoughtful reviews, and Glenn is thorough and sometimes funny. They only very rarely do or say something cringeworthy.
I also enjoyed reviews from this one guy names Hey Spanky! because often he wouldn't figure out what an accessory is for or how to articulate a certain figure, and would use it wrongly or get pissed at it. I found those funny but IIRC he hasn't done a review for like a year.
I've watched the most common ones /toy/ recommends like Thew, Vangelus, and Optibotimus but I don't like Transformers so none of them interest me.