I tried several plugins for frontend posting before I stumbled across WP Frontend User Pro. I absolutely love this plugin. It does everything I need it to, and does it extremely well. The setup is easy to understand and implementation is a snap.
Also, I've found the developer's support to be top notch. I recently needed to contact them in order to remove an activation from one of my development sites. I didn't have to wait days or even hours for a response. It was minutes and the issue was completely resolved. It's rare to receive customer service like this.
Overall, I have been extremely satisfied with my entire experience. These folks are doing it right all the way around.