Plastering advice needed

Hi,
We have built a new house and were are using insulated boards internally on all the external walls. All our internal walls on both floors are block walls should we just use sand and cement and then skim or should we use plaster boards on all walls and skim. I have spoken to the plasterer and he said the price would not change either way, I would have thought there would be a saving. Don't know which would be the best option so all comments welcome.
Thanks Zander

Personally, I would go with the sand/cement render and skim finish:

- more durable long term (ie hard to put your boot through it!)
- better base for fixings such as rads, shelves etc
- slightly larger rooms also as a result.

Rate for render + skim would be about 20 - 30% more expensive that dot/dab + skim
(in UK anyway), so I would advise your plasterer to fill his boots!!!!

You would also want to check with your chippy on what width frames are being hung as a dot/dabbed wall will probably be more wide than a s/c and skimmed finish.