I've used many types of electric vented (Euro and US) and condenser dryers. I've used one heat pump dryer (my current Miele, which I've had for two years). I used to have a Maytag Neptune gas dryer.
I have to say that I never noticed any difference in the smell or feel of clothes from that gas dryer and results were excellent (except it didn't reverse and thus balled bedding, driving me nuts). The only time I could detect any kind of combustion (or non-electric type of smell) was on opening the dryer mid-cycle and sticking my head pretty much inside the drum. Whites seemed to stay just as gleaming white as I'd expect from an electric dryer. Having said that, I only lived with it for a year so I didn't get the opportunity to see any potential long-term effects on old fabrics over many years. Perhaps it also depends on the model of dryer and whether it is correctly adjusted and functioning properly e.g. burning cleanly and at the right temperature etc.
I have to say that I never noticed any difference in the smell or feel of clothes from that gas dryer and results were excellent (except it didn't reverse and thus balled bedding, driving me nuts). The only time I could detect any kind of combustion (or non-electric type of smell) was on opening the dryer mid-cycle and sticking my head pretty much inside the drum. Whites seemed to stay just as gleaming white as I'd expect from an electric dryer. Having said that, I only lived with it for a year so I didn't get the opportunity to see any potential long-term effects on old fabrics over many years. Perhaps it also depends on the model of dryer and whether it is correctly adjusted and functioning properly e.g. burning cleanly and at the right temperature etc.