That's not a bad idea Ving.. I think you'd need a specialised "review form" for each "type" of equipment, but it could work. I'll give some thought to creating one.
Silvie, there's no hard and fast rules.. i'm just thinking about some book reviews I've read

There's a couple of book reviews in the latest S&S, and maybe the AS&T as well.. see how they write their reviews.
I guess you'd want to outline the facts first, like the title of book, the author, the publisher, # of pages, ISBN etc, and then a bit of your subjective/objective thoughts about the book..
the aim of the book, the chapters, how it was written, how easy it was to follow, factual or narrative, what you got out of it, whether you'd recommend it, who you'd recommend it for, etc.
Just a few ideas off the top of my head.
Appreciate it if you do end up taking the time Silvie! Thanks.