I have back isues and have always found cloth seats to be more comfortable. If you have back problems, the more firm the seat the better. A soft seat feels nice at first, but it isn't supporting you, which will make your back tired. Same goes for leather, you slide on it and it dosn't give you the suport you need.

After my injury, the insurance co. payed for a Recaro seat for me. It is very firm and has a suspencion built in to the frame rather than the cousions and the lumbar suport is properly positioned (American vehicles always have the lumbar support to high).

I find the cloth H3 seats comfotable enough that I havn't gone to the trouble of finding someone to custom build a bracket to fit the Recaro in the 3.