I would agree on the buy decision and I've often wondered why anyone would build their own monitoring system. And if I couldn't buy a solution I would look at several free or low cost monitoring tools before rolling my own.

I've seen Ops Mgr (SCOM) 2007 presentations at the SQL PASS Summit even though Ops Mgr isn't "free". So, perhaps as long as its a Microsoft monitoring products its OK 🙂

My local SQL user group has a no vendor product demo policy. Some of our user group attendees are from small shops that lack any tool funding and feel, rightly so, the product demos are of little value to them. I on the other hand, find the product demos useful, but I guess that's what vendor exhibit halls are for.