I only own the ego, but I understand the cone on the Riva is a slip fit as opposed to the Ego which
threads on. It seems the
threaded cone on the Ego would be more secure and it Does do a good job of containing any leakage in case of an overfill or if you drip straight into the atty (which I do most of the time). Not sure if the Riva cone would be as close to "leak proof" or if it depends on an oring or something similar to hold it on which might be prone to wearing out. Also the button on the Riva is rubber vs hard plastic&lighted on the Ego (just a personal preference thing).