A rain shell or windshirt will block wind and hep retain heat in the layers you have below, but won't have any insulation value past the wind blocking. There isn't going to be much difference in warmth between one brand of rain jacket or another. They will vary in breathability, water resistance, durability and feature sets, like hood construction, pit zips, etc.
What you are wearing under is the layering you can vary to suit your level of activity and conditions. That's where you get to choose from a wide range of wicking base layers, fleecy mid layers, and synthetic or down lofted layers.
I use a base layer, R1/Power Dry, windshirt, synthetic fill vest or jacket and poncho or rain shell as my 3-season layering system. I take a fleece beanie and light gloves as well. On the bottom side, I wear zip-off nylon pants or light soft shell pants, with silk weight longjohns and rain pants for colder/wetter weather.
Always view your clothing choices as an integrated system rather than a loose arrangement of favorites. That will give you the lightest weight and the greatest versatility.