If you are looking to get some insight into potential investors TheFunded.com has a rating system that let entrepreneurs rate their investors. The interface is pretty ugly and is missing smaller players, but the data is robust on the larger funds.
Seed-DB has a graph comparing Seed Investors and is completely free.
Perfomance Comparison with Free Trials
Fund Analysis - starting at $499/month Bison offers Market Insights Performance Calculations for LPs and Founders 14 day trial
Both Fund and Firm Analysis - starting at $1,199/month CBInsights has an investor Mosaic empowering Limited Partners and Founders 30 day trial
We published this article on how to use each.