There really is no best because it depends on personal sleeping preference.  But top rated pads are

Themarest Neo Air XTherm is the default choice for colder conditions...

https://www.rei.com/product/171689/therm-a-rest-neoair-xtherm-sleeping-pad

although the XLite also meets your criteria (R 4.2) and is lighter, cheaper and possibly more comfortable in warmer conditions.

https://www.rei.com/product/172126/therm-a-rest-neoair-xlite-sleeping-pad

Some complain XLites are loud but personally I have never noticed it being a problem.  Lots of choice on size depending on your preference.  I have a Regular (6ft 195lb) Would probably get a Regular Wide.  You can also cut them down and reseal them for a custom length if you care around weight.  If it fits you the 5ft6 women's version is warmer and worth considering.

Comes with a patch kit that works well...I have tested it. No fault of the pad 😞 

https://www.thermarest.com/products/sleeping-pads?prefn1=ID&prefv1=NeoAir

The other well rated pad for comfort is the Nemo Tensor although I have never used one.  Supposedly quieter and a bit more support on the edges but it is heavier and I think bulkier than the Thermarest X series.  Also available in various shapes and insulated or not.

https://www.rei.com/product/141845/nemo-tensor-insulated-sleeping-pad

https://www.nemoequipment.com/product/tensor/

Note: Any inflatable is prone to puncture and if you are using it around pointy thing (eg deserts have catcus spine and thorns) you should consider protecting it with some resistant base  (an 1/8 inch Evazote foam pad in addition to whatever ground cloths your shelter uses is a light useful way to do that)