As has been said by other posters, I like HPIGuys Workshop for what it is: in box reviews of kits & what they'll look like when done. I like how he presents the kits in a manner of fact way and will point out faults & issues when they exist; however, I must say that he is a much more experienced modeler that I am so where he doesn't have issues with a certain assembly, mine might be a complete disaster. I also enjoy his enthusiasm, which I have to stop myself for falling for sometimes. I believe Chris is a salesman in his "day job", and could probably sell ice to an Eskimo, so I have to be careful. I have purchased several kits on his "recommendation" & video build. Some of them have been successful, some not so much. Taken for what HPIGuys Workshop is, I think it's a very good channel & a good resource for what the kits are. A couple more channels that sort of fall into the "build out of the box" category is Building on a Budget Models and HPPworks. Straight-forward builds. Nothing too fancy.
If I am looking for videos of model building techniques, I will generally just do a search on a particular model & see what comes up. One channel I found this way was Make it scale, which is quite good. Another one is autostrada macchina. This guy is GOOD! As is Scale-a-ton. Insane detailing, although he does dis on 1/25 scale as being a "flaw". European thing, I guess.
I guess what I'm trying to say is that there are lots of channels out there, and it just depends on what you're looking for: in-box reviews, build reviews, detailing, or crazy super detailing. They're all out there, you just need to look.