A boiler that works hard and is not short cycling is miles more efficent, also the back-end temp (FGT) will be higher so less chance of it rotting out quicker.
I am interested to get some more info on your system chris, any chance of the following information.
1. size of unit in KW and the make
2. system load in KW
3. House type and plan, ie: semi detatched bungalow
4. approx cost of electric used per year
5. room stat setting in 'c
6. timer run time in hours per day
I have no direct expierence of this type of system but others in the trade have slated it when we chat in the merchants, so it would be interesting to know the above information , as your system clearly works and you are happy with it.