The post was in regards to Paper Shredder Reviews , which is a fairly specialized site.
The Short Answer:
Depends on your time and resources.
If you have lots of time and resources create the larger more general site. If your resources are limited create the smaller niche site.
The Long Answer:
The paper shredder site scope is limited. Yes there are much bigger search terms to compete for. One thing to remember, there is much stronger competition for the more popular search terms. When you go after the smaller targeted terms they are often easier to compete in, allowing your to rank higher with less effort.
If I were to create an office equipment review site, more resources would be needed. There are more items to research, more product attributes to code and add more products in general. Then I would have to try to rank each of the different types of office products. Much more information to manage.
When I work with the paper shredder site, the products and product attributes are similar. There is less research needed and fewer products manage. In terms of SEO, the domain says paper shredder reviews, the url contains shredder reviews, and all the pages that link to each other are about shredder reviews. With all elements being about paper shredders it will be easier to rank for paper shredders.
Compete to win, whatever you do.
In my opinion it does you no good to be on page two of Google.