Amazon review Sites - Should I do one large site full of reviews or smaller niche specific sites?

Hello all. I am starting to get into promoting amazon products quite a bit but I still have a decision to make about my site(s) that I haven't decided on yet.

I am wondering if it is better to go one large site full of many different product reviews or do many smaller sites in which each site targets a certain niche.

Here's my reasons for each:

I have a domain name that is a more of a general review site and the domain name is a couple years old with PR1 and a few hundred backlinks in Google so it has allready gained some Google trust. Also I figure that using this site and adding many reviews will make it easier to rank the reviews as the site allready has that Google trust factor. Also, looking long term if I build backlinks to only one site and build backlinks across just one site it will help increase my PR and authority over time so it would essentially be easier to rank reviews in the future (maybe).

On the other hand my reasons for wanting to build many smaller review sites that each target a specific niche are this. once the sites starts doing well and making money I could sell the individual sites for higher profits on somewhere like Flippa but with only 1 site I couldn't do that. Also the little sites would all be using new domain names that have no trust factor yet and therefore probably wouldn't ranks as well as fast and would probably do the Google dance a lot more first as well before it would get a god ranking which could take a while.

So I would like to get some feedback from you guys if you don't mind on which option you would go for a why or which option is best. thanks a million.