Given this guy a quick run. I think it's a great product. I've been using SQL Nexus over the last fortnight as well, and am thinking that you'd benefit from using both products (especially since Nexus is free) to keep a good overall view of server health. For example, there are a few key counters missing from the Performance snapshot on SQL Response, such as Page Life Expectancy, Memory Grants Pending, Plan cache hit ratio etc.
I especially loved (possibly because we have a small bumber of servers) how quick and easy it was to setup, as I recently found also with SQL Backup. Microsoft would do well to pay attention to RedGate's UI designs.
Very impressed with Response, but as always with a first release there's room for improvement.