Big site or 1 product niche site?

There are pros and cons of each Big site Vs niche sites, here are some pros and cons of each I found. What are yours?

Big Authority site pros:

1. one domain buying (cheaper)
2. easier to get backlinks to, instead of 12 sites
3. Big G. loves big authority sites
4. Maybe bit easy to maintain (do not have to add template, plugins all again)
5. one can have umbrella list of products (example: all digital cameras) in one place. having more choices of products.

Big Site Cons:

1. Take time to set up.
2. People might be confused with various posts and products links.
3. Not specific enough.

Niche site pros:

1. Very specific to individual product, like modelname-size-brand
2. having keyword in URL helps already
3. People searching for specific keyword are already looking to buy, no need to pre-sell them
4. only 2-10 pages, easier to create, fast up and running

Niche site cons:

1. Way too specific for product, make sure there enough searches
2. You may need to create more niche sites to take care of same brand's other popular products, may need many niche sites
3. You need to find backlinks for each sites, instead of just one.
4. Some niche sites can look spammy (not all)

To niche site or authority site, that is the question? What works for you all, please add your list here for others.