Never used a cache like this before. The problem is that I want to load 500,000 + records out of a database and do some selecting/filtering wicked fast.
Choose a cache which complies to JSR 107 which will make your job easy when you want to migrate from one implementation to the other. To be specific on the question go for Ehcache which is more popular and widely used Java caching solution. We are using Ehcache extensively and it works for us.