As mentioned there are two installs available for vCenter Operations. The vApp is actually preferred/recommended for most customers and includes all capabilities of the installable version. The installable or standalone version does not include capacity management features nor does it include the ever popular vSphere UI you may have seen during demonstrations of the product.
You will be able to monitor physical infrastructure with the vApp, provided you have also purchased additional third-party adapters (which are required regardless of which install you go with).
Highly recommend that you go with the vApp.