In our experience, SSF takes longer than Smf of the same substrate. This is particularly true for fungal processes. We have  used a number of crude substrates for fermentation, including Apple peels, banana peels, corn cob, bagasse etc. The reason can be attributed to the time taken by fungi to invade the substrate in absence of water. 

Dear Muhanmmet,

SSF process is generally used for production of extracellular products such as enzymes, chemicals etc where the fungi are the main sources of production. Normally these products are produced in huge quantities even at very low water activities (however maintaining humidity levels is very crucial) and generally grown on wheat bran which has many inducers to promote the growth of fungi and production of various metabolites.

There is no comparison between SSF and SmF. Some processes work best under SSF and some under SmF.  Cultivation time is usually longer in SSF as compared to SmF in general. (3-5 days fermentation),  But again I would like to emphasise that the choice of SSF and SmF is totally dependant on type of product, cost of product and quantity of product. SSF is much cheaper than SmF process in many conditions....

I donot agree with Deepti on the point that cultivation time is ususally longer in SSF. There is no comparison between SSF and SmF. The cultivation time depends upon several factors including the application(product of interest), organism, culture conditions. e.g. Our group has worked upon cellulase production by fungal strains, both in SSF and SMF and we found that Smf took longer (comparative to Smf). 

so unless the particular application is concerned it is difficu;lt to have any generalised idea about this question.