As Troy knows, I'm working on one at the moment. But my gut tells me to characterize it as an overview, not a review per se for the following reasons:
1) Most accessories (or grill models, even) are "worth" getting for anyone interested in this hobby. That is, darn near everything can be made to do good cookups somehow. Don't have that accessory? No problem, you can still do the cook another way most likely, right?
2) If you paid money for it, you're invested. You do have some confirmation bias for rationalizing the purchase. It'll more likely be positively reviewed, which reduces the review's value IMO.
3) Reviews work best (again, IMO) with the reviewer's recent experience of competing products and if I had one suggestion it would be to write something in that vein and not treat the review subject as an isolated product, because they never are. Give an opinion, it's OK.
So long as the reader understands the writer's priorities and values, they should be able to read a "negative" review and still come away with an interest or desire to purchase it if they know what's important to them differs.