Please incorporate a captcha mechanism to the login page. Otherwise, OpManager is vulnerable to dictionary attack.
Being able to check in on the current condition of the production environment using OpManager from anywhere and any device is a very good thing. This is particular true for large organization and with employees traveling frequently.
Notice, using ssh or vpn to create a private connection is still not good enough. For example, what if I am at a relative's house and I wanted to check in on the production system? In this case, my relative's computer would not have ssh or vpn.
By the way, this is really easy to implement since there are a number popular open source / free solutions.