Feature-rich and easy to configure, it finds all feeds automatically and very neatly deals with them — and adds plenty of configuration options for each individual feed. Loads images, authors, etc. all automatically, while still making sure that proper attribution is maintained (e.g. the feeds can be configured so that an excerpt shows on the aggregation site, but the link for reading more correctly forwards to the original site). It does pretty much everything expected of a syndication aggregator.
It also allows extra plugins to be created to work with FeedWordPress, thus allowing extra functionality to be further developed without needing to "hack" the original plugin.
My only issue is with duplicates. While FeedWordPress tries to do an awesome work to locate and eliminate duplicates, it's not 100% perfect (but perhaps 98-99% perfect). Sometimes a few articles get duplicated, specially when feeds change or are very slow in loading (thus, FeedWordPress might not be to blame).
Besides that, this is a quite welcome plugin!