The OP's opinion on her songs is spot on. If you read alot of the posts, primarily the ones about ten or twenty in, you'll notice alot of the "Repetitive, lame, again" posts followed by the "Sounds the same, turned it off" posts shortly after.
I'm actually embarrassed by my RMM badges. I watch the videos to see if they actually are that bad. They are. Though she does have a 14-day turn-around time for these videos, they still seem like they've been hashed out and pasted together in under a week. This shows in the lack of creativity in the lyrics, as well as the direction in the video. Her videos are supposed to be reviews of video games, but they provide little usable information. I've been able to garner more meat from blog reviews less than three paragraphs in length.
On top of this, her musical ability is actually lacking. Yes, she handles instruments in her videos, but her ability to play them is at the very least, questionable. Unless accompanied by Garage Band or a Xylophone, I doubt we'll be seeing any Rebecca Mayes On Tour ideas popping up any time soon. She can definitely sing, though. Is it good singing? No. As an experiment, I've been covering her lyrics she adds to the video to see if I can make sense of what she says. I don't know if it's me or her, but all I hear is melodic gibberish. I'm sure she's aware of this, or else she wouldn't have even bothered including the lyrics in her videos.
I don't hate RM, nor do I like her. I suppose I tolerate her, but that tolerance is finite. The moderators that prowl her threads come off as biased and somewhat Stalinist. I've been the victim of their "Say good things or don't say anything" style of iron-fisted thread-mongering whenever I make a thought out and well formed critique. At least I don't do what I believe some of her fans do; mute the volume and masturbate.