I just bought one of the renewed 212s (which are in fact pristine open-box 202s) from Amazon to replace my 200. There was nothing wrong with the 200, as it happens; after 7 years, I was just itching for an upgrade.
Besides the Phone 2 jack, the only difference that I can see is that the 202 has some beefier router-like features, such as QoS. If you're not using the 202 as your primary router, I really can't see any of those features getting much use. All other features are exactly the same—including the 4 (max.) SP slots. In fact, I manually copied over the settings from my 200 pretty much line by line.
I actually wish there were 4x SP slots per phone port, making a total of 8. I've been paying SIP Sorcery $70/year just to aggregate some lesser-used SIP services with DID that I maintain in countries where I used to live. Would be nice to cancel SIP Sorcery and bring them in-house on a single device.
Anyhow, hope that helps clarify the differences between the two.