It's really good that you're looking for professional critique - that's a really helpful thing to have! However, a Kirkus book review might well be the wrong address.
A Kirkus review exists to help people find books they want to read, or to choose whether or not to buy a particular book. What you're looking for is a critique - feedback highlighting both the faults and merits of your particular book. The two goals may be somewhat related, but for $400 and upwards, you can do a whole lot better than "somewhat related."
I've just browsed some of the Kirkus indie reviews. Look at those and see if that's the type of criticism that you think you'll find helpful. Notice that in general, the reviews are half a simple description of the book - not very important to you, but extremely important to people who want to know "what the book's about" - and half opinion as to what in the book works and why, mostly in general terms addressing the novel as a whole rather than going in-depth to characters, scenes, etc. That's not unhelpful. But it's not a whole lot, either.
In addition, a serious concern is how reliable the Kirkus indie reviews are. The ones which I've browsed often portray their books as a mixed bag, with some things done well and others serving as flaws - so this isn't a "buy a glowing review" scam. But even mixed reviews can be suspect. The tone, phrasing and generality of many of the partially-positive review makes me suspicious that "the good stuff" is simply "the least bad stuff," portrayed positively so that the reviews don't all come off as excessively negative.
This suspicion is acute because Kirkus is pitching to self-publishers here, not to readers. When your target audience is readers and book buyers, you succeed most if they come to trust your reviews. When your target audience is self-publishers, you succeed if they think they're getting good publicity for their books. Note how the Indie reviews are held seperate from the regular ones - they're aimed at two different segments. So, if you consider pursuing such a review for feedback purposes, then you really want to check out how reliable the reviews are. Maybe read a couple reviewed books yourself, and see if the reviews match; at very least look for unbiased reviews elsewhere.
Those are all reasons Kirkus sounds to me like a poor option for feedback (for publicizing your book, that's a whole different story, which I won't get into here). Here's are two suggestion I think might be more appropriate.
Firstly, you started out asking for qualified, non-biased, and thorough feedback. How about two out of three? There are many venues for getting your work critiqued by fellow writing enthusiasts. I'm personally a big fan of the Critters workshop, which has a well-established track for getting novel critiques. If you've never been in a workshop or a critique circle before, you might be surprised how helpful they can be. Readers may not be "qualified" editors, but they read and love their genre - they're the type of reader you're writing for, so at very least, they can be a great guide to whether you're getting across what you'd like to, and what impressions random readers have from your work. And these aren't random readers - these are readers who write, and some of them know a little about it. Of course, if you get somebody whose criticism resonates with you, then you'll find that incredibly helpful, even if it's not professional-level. A lot of feedback from a hobbyist beats a few lines of feedback from a pro.
Similarly, you can probably find friends and acquaintances who can be a big help (if you haven't done so already). What's most important is that (A) they be somebody whose opinion you respect, and (B) they thoroughly understand that you prefer honest criticism, even if harsh. When soliciting feedback, what's most important isn't suggestions for improvement - most amateur suggestions will not be immediately helpful or beneficial. What's important is understanding what the reader's response to the book was. That's what they can report on unerringly; how you can improve your work to get better responses is an issue for later.
Again, these might not be qualified critiques, but they're extremely helpful in gauging where your writing stands. Jumping to a professional review without getting more modest, accessible feedback is a waste - because really, why not get both? And why not get the expensive feedback after you've made as many improvements as you can with the free stuff?
Secondly, consider hiring an editor. Editors and reviewers hire out same as everybody else; find somebody who can do the job you need, rather then the job Kirkus is offering. Offhand, two blogs I follow do review work for pay, Nancy Fulda and Mette Ivie Harrison. I'm not recommending these two specifically (one of them isn't even an option - Nancy Fulda only accepts new clients by reference), but they can give you an idea of what services to look for and what kind of prices to expect. If you go this route, WATCH OUT FOR SCAMS.
Any way you wind up choosing, best of luck, with this piece and with future ones!