Do I need a primary and secondary regulator?

It depends. You need to decide what style beers you will be drinking. If they require different carbonation levels then you will need to be able to set two different pressures. So first do some research on what you will be drinking and the carb level of those beers (Google is a good place to start).

If need two pressures you can accomplish this with the dual primary regulator in your link . . . or a single primary that feeds two secondary regulators, http://www.micromatic.com/draft-keg-beer/regulators-pid-8221.html

Either of these setups will give you the ability for independent pressures. If you only require a single pressure for the two kegs you can accomplish this easily with a single primary with a "wye" output, http://www.micromatic.com/draft-keg-beer/regulators-pid-642-2.html. If you go with a single primary only you can always add on another primary or a bank of secondaries. Many distributors will be glad to do simple modifications to their products if you are ordering new from them.

Your beer will not know the difference on how it's being pressurized. Your physical placement of your tank/regulator/kegerator has a lot to do with which way you go (it must fit!).

You didn't ask, but discount regulators almost always cost more.

 

If you don't want to be screwing secondary regulators into back wall of unit. Then I suggest a dual primary regulator.
Take a look at my video of my unit to see what a secondary regulator setup looks like.

 

Thanks.. No reason why I chose secondaries over dual primary.