Sorry about the post with no body, and thanks for the response. I hate this forum's mechanisms for creating new posts btw.
Anyway,
I was in the middle of creating a new post including all the specifications, and they seem virtually identical in terms of QAM, etc. I checked the MAT comparison chart before ever making the post. It is my "go to" source for AP and Controller comparisons. The gain on the 225 is slightly lower, so perhaps it could be used in a higher density environment. The 225 advertises 802.11g/n 600 Mbps max rate, while the 215 advertises 802.11g/n 450 Mbps max rate. I cannot see why the 225 has a higher advertised through-put in 802.11n. The 225 does have a 2nd ethernet interface for 802.11ac speeds above 1 Gbps, but honestly I never consider those speeds as realistic unless in a residential application due to not being able to utilize 80 Mhz channels, and almost no clients ever fund dual cable feeds per access points due to capital limitations.