I have the 250, 4E Arctics, and 4E Halo 3D. I think it goes Arctics, 250, and then Halo 3D in order of warmth.
The 4E stuff is a lot less bulky, it is more dense. So while the 250 is bulky it will compress a good bit. I find the 4E stuff easier to dive and more comfortable overall.
I really...