What is a heterogeneous environment? Well, what it's not is a the place where a really smart straight guy lives. What I'm getting at is really every IT shop. You may say "Hey, we only run Windows" or "Dude, we're purely SUSE here" but stop for a moment and consider those switches, routers, and UPS' in your IT shop. Are they Microsoft? Novell? Yeah, didn't think so.
So what we've established at this time is that we all work in heterogeneous IT environments. And quite likely, certain aspects of them are managed. Probably quite well (I'm not making the assumption that you can't do your job). But what's the big picture? Are you viewing things as storage, servers, networks, applications, et al and each a world unto itself? This is quite likely the situation.
So back tracking again, we've got our IT shop made up of bits and pieces from various vendors, all working together to deliver some sort of service to our end-users. Now we want to manage the whole shooting match. Get all the system stats, performance data, and alarms into one consistent view.
Well, if you go to any of the tier one vendors, they'll tell you this is simple. "Buy our product, some consulting hours, and you're done." You're done alright. You can have the consultants come in and roll out a great solution, that works for the first few weeks. What you really need in place first to underpin this architecture and provide long-term valuable metrics on your heterogeneous IT environment is a baseline, strategy, and process. Tools can come later, and with the toolsets on the market today, can be largely interchangeable & interconnecting. That's not in any way to dismiss the amount of work it takes to set up the tools correctly in the first place, that IS a lot of work.
What I want to stress here is that managing a mixed IT environment; managing all of your systems components; having that BIG picture of IT service delivery needs a good baseline/audit of what's in place today, a top-down strategy going forward, and processes that work with your people & business practises.