I use the Reddit API to extract the most recent 100 comments from a user. I take those comments and extract sentences that aren't too long and aren't too short. Each sentence is then analyzed using the NLTK Sentiment AnalyzerVader Module and scored based on how positive, negative, and neutral it is. I then rank the analyzed users in order from most positive to least positive.
Hutto, C.J. & Gilbert, E.E. (2014). VADER: A Parsimonious Rule-based Model for Sentiment Analysis of Social Media Text. Eighth International Conference on Weblogs and Social Media (ICWSM-14). Ann Arbor, MI, June 2014.
If you have any questions please pm /u/opfeels. If you like this app and want to throw a few bucks at the developer, you can donate here: Buy /u/opfeels a beer!
Update 1/4/16 (/u/opfeels bot): I've turned my account into a bot that will reply to any comment that mentions my name with any other name. Example:
/u/spez is very positive! view results - Ranked #13609 of 47558