Sorry, I know you worked hard on it but this comes from real experience. We had an absolute nightmare debugging strange issues in the cache and traced it to this. Probably an older version though.
Each threading issue reported ended up being traced back to sharing a RedisClient instance across multiple threads, e.g. by using a static RedisClient instance, registering RedisClient in IOC, etc - i.e. instead of using one of the ThreadSafe connection factories. If you have any repro showing any multi-threading issues with proper usage we'd love to hear about it (https://github.com/ServiceStack/Issues).
