Two questions:

1. Does plesk7-reloaded comes with Tomcat?

2. For ensim, all the add-on and upgrades are free. Why is plesk so different? I visited the plesk website, they charge a lot of money for those add-ons.

no tomcat is not included..
Because swsoft want to get the more money from you

Maybe b/c of ..... money?

I would have to add to this that sw-soft charges for the add-ons seperatly so that they do not have to include the cost of each of this items in the base price of plesk...therefore allowing plesk to be priced a bit lower. But, that's just my .02 ...you might want to ask sw-soft directly about thier pricing, if you believe there is a problem

(I should also add that ensim used to charge for add-ons as well..and ensim definatly charges for version upgrades..unless that has changed recently....I should also note that most of us never see most of the charges as ev1 (headsurfer) takes care of all of that for us).