See this posting for modifying the lights to LEDs and other mods made by this RSM 650 owner.
nob35's S650
I have the RSM 650 and enjoy it. But, you are comparing a 150 gallon display tank to a 210. Seems to me like the size difference is a significant factor to consider. You are right about the finished look of the RSM. That is why it was a relatively easy sell to my wife. Also, with the RSM, you don't have to buy lights, skimmer, ATO, circulation pumps, etc. That makes it pretty easy to set it up, put water in it, and be done. I've added a chiller, a couple of reactors, and a Reefkeeper Elite controller.
But, if you enjoy selecting all the options and customizing, I would see the 210 as the way to go. That way you could get the LEDs you want and might not have to have a chiller. But since you're in FL a chiller is possibly already a done deal.
I don't like the power control center on the RSM. The pumps are not controllable so the flow is the flow...few options. Also, the lights are not dimmable. You either have all ten on, eight on, two on, or all off. Those are your only options. Also, consider that you will need to change the bulbs every 9-12 months.
I don't mean to sound negative on the RSM 650 but I wanted to give you what I see as downsides. If I had to do it over, I might go another direction. I've learned a lot about setting up a system over the last 9 months.