Using this plugin with Excerpts&Thumbnails. Started with WP RSS Multi Importer, but this plugin wasn't capable of handling many feeds along (with images) in the shortcode. WP RSS Aggregator doesn't have this problem. Everything is stored and retrieved efficiently, and your page won't lose any speed (loading in <1 second compared to roughly 10 for WP RSS Multi Importer for 15 heavy feeds).
Had a tiny issue with the comment section remaining open on the page with the shortcode. But the support team responded quick and thorough, a fix was released immediately.
Overall, great functionality and support.