Neutron from iZotope is a mixing channel strip with EQ, Compressor, Exciter, Transient Shaper and Limiter. The presets and Track Assistant quickly gives you a good starting point and the Masking Meter helps to avoid frequency collisions.
FabFilter Pro-L is the most impressive limiter I have tried yet. It has a unique real-time level display, output and level meters with inter-sample peak detection and K-system support.
Price: € 169
Frontier from D16 Group is an easy to use mixing/mastering limiter with excellent sound quality. It features automatic output gain make up, configurable control input, controlable release charecteristics and optional soft clip.
Price: Free for registered D16 Group users.