My tank is only a 180g, but I also have a 70g anemone tank, a 55g local tank and a 24g frag tank. All together I had 6 250W MH and 320W of t5 1 year ago (1850W always at 100% power). Today I have 3 EverGrow IT series fixture over the 2 DT's and 3 OceanRevive dimmable fixtures over the 55g & frag tank, that's 960W of led
at full power. But on average they run at about 60% power, and deliver a PAR of 200+ at the sand and they all grow sps and clams, no problems. They are Bridgelux leds, you don't need Cree. They are more efficient and have more output, but a PAR of 200+ at the sand is way more than enough light. And look for the ratio of blue to white leds in the fixtures you consider. Reef Radiance is about 1:1 and for me, that's way too white. OceanRevive, EverGrow and Reef Breeders are all more like 2:1 and even that's just barely enough for me. I run mine with the blues at 80% and the whites at 40% and it's a nice 12K-14K MH look in the tank and 200+ PAR at the sand.
OK so my lights use less electricity, I also have a 1hp chiller and a 1/3rd hp chiller, and now they hardly run at all. And being in SW Florida we allow our house to run at 80 degrees, but this summer, since the switch to leds last December, our house A/C runs less too! Over the June-Oct A/C season our electric bill has gone down $45/mth on average. I'm guessing we will save between $350 and $400 in electricity this year over last year and our electricity rates have gone up! Add on to that the fact that I'll save $160+ in t5 bulbs (I change them every 12 months) and $250+ on MH bulbs (I change them every 18 months and the $250 figure is averaged over the 18 month time frame). So altogether I'll save between $750 and $800+ just in 1 year. And I only paid $1300 for the 6 led fixtures I use. You have to love MH light and heat not to seriously consider the change.
I know I like the leds. Being able to start the day with a blue dawn in the tank and slowly ramp up to a white midday over 8 hours and then wind down the next 8 hours to a blue dusk... I love to watch the tank change all day. And the corals are just as healthy and growing just as fast (maybe faster) than they did under 1000W of MH and 160W of t5 over the 180g DT. BTW, it's mostly sps and lps corals.
Here is a FTS from about 4 months ago, after being under leds for about 8 months.
And this hanging birdsnest colony was a tiny 1" frag, just broken at one end and one growth tip at the other 8 months before this photo. It was easily 6" in diameter here and is well over 8" in diameter now. So it's entire life has been under my EverGrow OR-IT2080 led fixtures.

I'd recommend you get 2 of the OR-IT2080's and maybe 2 Arctic S026's or OR-IT2040's for the back of your 250g tank. If the OR-IT2080's are enough (depending on how big your tank is front to back), your only looking at $775 delivered. If you need to add the Arctic S026's in the back, that's an extra $300. You'd save all of that in 2 to 3 years of electricity and bulbs. And you can always sell the MH after you decide you like the leds. There are a lot of people who still want MH lights... I sold mine after about 6 months of letting them collect dust.
Good luck whatever you decide.