I think that Janet is an expert on the things Janet wants in a query.
QFT. And she's addressed the fact that she's not like all other agents in various places in her blog.
Many things transfer well, but if the agent you're querying says that they want a logline, or if they say in their guidelines or in their blog that they don't want the pitch part of your query letter to be more than one paragraph, it's probably a good idea to tailor it to what they say they like.
For me, in the absence of specific information about what the agent likes in terms of query format, I've been sending my "Janet Reid" style query with (when the information is available) a line near the end of the query about why I think this particular novel might interest this agent, or why I am querying them.
You say you're a sucker for romantic subplots.
You say you like stories about outsiders.
You say you have a weakness for stories with dogs in them.
You say you like fantasy in settings that don't feel just like the middle ages.
You rep so and so, and that's the style of fantasy I'm striving to write.
I was at a writer's conference where you gave a talk about X that was really interesting and helpful.
I follow your blog, and I really appreciate the advice you give to writers.
I don't think it hurts to let an agent know you've read their web site and/or blog and gave the query a bit of thought, rather than just shooting a form letter out by the dozens.
Sometimes, though, there's really no information at all, and I'm just just shooting in the dark. With those, my letters tend to be fairly generic. Take these thoughts for whatever they're worth, since I'm still querying, and haven't gotten past the polite "not quite form rejection" on a couple of fulls yet