I've used both extensively. I disagree with this. I dislike the HP48 series but I dislike the TI89 more. It's probably because most people don't understand how to use the 50G properly. You really need to go through the HP training video ( https://www.youtube.com/watch?v=OTPruRVV-e8 ). Incidentally if you haven't watched that it's worth watching on its own - great production! In an engineering context, the 48-series was designed to produce small composable reusable programs and tools in the file tree which can be executed quickly.
Try a quick EE example for parallel resistor calculation that takes 2 and puts 1 value back on stack
<< 1/X SWAP 1/X + 1/X >>
Store that in RPAR in whatever directory you want or HOME. Then you whack in 2 resistors and hit the RPAR F-key. There is nothing faster or more efficient than that.
I still use a 15C all the time though. Even easier! 99% of what I do is on paper though and ends up getting chucked in the numeric solver.
Try a quick EE example for parallel resistor calculation that takes 2 and puts 1 value back on stack
<< 1/X SWAP 1/X + 1/X >>
Store that in RPAR in whatever directory you want or HOME. Then you whack in 2 resistors and hit the RPAR F-key. There is nothing faster or more efficient than that.
I still use a 15C all the time though. Even easier! 99% of what I do is on paper though and ends up getting chucked in the numeric solver.