The rlm guys are very insightful and have great taste in movies. I think the difference is that they do a great job explaining why a movie is entertaining while Ebert was great at explaining why a movie is art.
RLM guys (at least the main ones) seem great at pointing out when a movie sucks, mostly because of:
- poor structure. Bad setup/payoffs, useless sequences, confusing narrative without any merit behind it
- poor pacing. Too much "brain-off" action, shitty dialog, too fast/slow for the theme
- uninteresting characters, with no redeeming characteristics (e.g. a great actor or enough plot quality to compensate)
These in decreasing order of importance for them -
They will certainly critize other things (plain scenes, bad framing, technical flaws, bad lighting, etc.) but I don't think I've ever seen them give a purely negative review based only on these.
If any of those three criteria above are met, though, (and god forbid all three) they will absolutely pile on a terrible rating with complaints on how the scenes are ugly and general filmmaking is lazy.
Oh, and also, they'll point out most editing errors, seeing as they are editors too.
And insert pointless Star Trek references no matter what, of course
Part of the joke with Mr Plinkett is nobody sane would do the sort of "deep dive" he is doing. It's not really meant to be an example of film criticism at its best.