Ok so I do grow pretty much entirely vegetables, but things like chillis aren't too different to flowers and things!
The jiffy plugs are great for seeds that take ages to germinate as they're fairly sterile and don't go mouldy in the propagator. However the white fabric thing round them never truly biodegrades- even though it claims it does.
The pots you have to bury, any rim poking up out of the ground won't degrade and you end up with
cardboard rings all round the garden. I found the pots didn't quite last long
enough for chillis and they started to grow fungus in the warm propagator. They were good for peas and sweetcorn and faster growing things.
I don't think the jiffy pots dried out significantly faster than my other plastic pots, they have a bit of a waxy coating that helps. The plugs dry out very fast.