I normally use MDR, but occasionally a mini-Dalton Computer Dead Reckoning Mk 5A for conversions. Also the TAS function for my heavier metal theoretical stuff.
The Nintendoverts of the play station generation can keep their electronic ones! And I say that having bought my first electronic calculator (Prinztronic Micro) in 1972 for 49 guineas. Still going strong - but it uses 0.5W of power from 4 AA batteries. Must be a collector's item by now!