Spannerhead,
I think that it is matter of preference. Hard rubber lasts longer, but you get nicks in the blades easily. Also if you are new you may find it causes thin lines(that are not your fault).
Soft doesnt last as long but we tend to get on better with it. we have tried them all and tend to stick to syr which is quit soft.
With cloths we have both. Dry work we use the microfibre. Scrim for edging up.
cheers john