There is an interesting article in this month SOS on effects plugins. The SIR was the only free plugging who got extra attention. Apparently, this plugin is not only good as a convolution reverb and mastering tool. For those who are on a budget, this plugin is a must have.
There was also a note on Korg's MDX effects which comes with their digital collection. As you know, effect plugins can become very expensive. In the case for the Korg digital collection, you get not only 2 great synths but the effect plugin (which share the same basis as the Oasys plugins) seems really usable. Not free off course, but it might justify the cost for getting that Digital Collection.