Categories are taxonomies so using a custom taxonomy is no different then using categories, but if you have for example categories with Action, Arcade, Strategy ...
and a custom taxonomy console with : XBox 360, PS3, WI ...
then you can use that to show reviews for games that are Action games and that are for PS3 much easier.
and if you want you can extend that with a price rage taxonomy, meaning create another taxonomy named for example
price_range with: under $50, $50 - $100, over $100 ...
then you can use all 3 taxonomies (categories, console and price range) to select just the games that are for XBox that are strategy games and cost less the 50$.
so basically in your case each taxonomy is a filter to select based on.
Update Per @gilgimech comment
If you use just categories for this structure then you would get something like this:
and that is without the price range , in this way you need to create the same categories over and over for each genre , each price range and each console, but if you use custom taxonomies the you would get something like this:
categories : arcade, action , strategy ..
console: ps3, xbox, wii ...
price range : under $50, $50 - $100, over $100
you only create each term once.
Now for example look at
game 1 which is a game for both xbox and ps3 and its both action and strategy, so instead of giving it 4 categories (arcade and strategy under ps3 and arcade and strategy under xbox) you only give it two categories arcade and strategy and you set the two consoles as console terms
but it's still 4 terms each???
Yep but your structure is much cleaner. And just think about adding the price range to the category structure or you will have to go over all of the categories who are children of (video game ) meaning the consoles and you would need to create a new term for each price range for each genre sub category, but if you add a custom taxonomy you just add each range once and you are done.
so its not just a smaller list of categories in the category tree, its much easier to work with and filter by, and its less work to do.