Your blog is clear about mentioning beta readers (nix). What about published authors? For example: "Tobias Wolff, who graciously read excerpts, characterized the writing as upmarket historical fiction."
I think I know what you're going to say: "Nix. Let ME figure out whether it's good or not."
Your example isn't a blurb, it's an author offering up a category. It's akin to "Lee Child says this is a thriller."
Given Tobias Wolff knows a thing or two about fiction I'd probably take his word for the fact that you're querying upmarket historical fiction.
Given I think Tobias Wolff is a terrific writer, if he said your book was the cat's pajamas, I'd be expecting furry flannel.
However, the risk you take in quoting well-known writers in your query is that I'm familiar with the writer's work and don't think much of it. Not all writers, not even all good writers, are to everyone's taste. Generally if I don't care much for a writer's work, I'm not going to give their opinion much weight.
And I'm also very suspicious of writer blurbs. I always think of the statement attributed to Robert Parker "I'll read this or I'll blurb this, but not both."
And I understand the complex world of teachers blurbing student's books, or favors being traded at the bar at Bouchercon.
In other words, I rarely take blurbs at face value.
All in all, I'd rather you simply tell me about the novel you've written and let me figure out if it's jammies for Jinxies.