Using the Big Agnes Insulated Air core gives the best of both worlds, as the insulation is on the top. Flipping it upside down makes it very similar to sleeping on a lilo, ie much cooler.
Lying down on my Downmat 7 on a hot day feels like putting a jacket on. I've never tried it on a hot night, and don't plan to. Plus it's a bit heavier than my Big Agnes.
The other option is a Neoair. Light, compact and comfortable and then add a blue mat on top of it when it gets cold.