I would just like to add that the Sci-Plus 300 calculators hardware is more robust then the old RNIB LC107/LC108 flimsy design. However, the performance of the Sci-Plus calculators is inferior for use in GCSE maths. One of the complaints we've had from users is that they cannot display the right amount of decimal points. The old RNIB calculators also have a nice tactile feel to them. Unfortunately, the LC107/108s had a short life-span mainly due to poor internal structure and poor battery life.
I remember 'back in the day' when RNIB gave tech support for these calculators, they advised me not to take calculators apart myself to replace batteries as they were 'special' and I should send them to the RNIB. As their support stopped, I removed the cover off one of them and discovered that they were plain old Ni-Cad AA batteries. I replaced them myself and got a few more years out of our calculators, but eventually they died.
If anyone knows of any good alternatives (but NOT software based calculators) please add this to the thread. Also, if anyone has any spare ones (yeah right...!) please do contact me as our students need them. I will continue to search for an alternative.
Or if you have any points to make about these calculators, we'd like to hear them...