If you need it, the field solver for high-speed diff pairs in Altium is head and shoulders above the approximation techniques in the online tools - which never agree with each other anyway. Kicad is no better than the online ones.
The price of a standalone field solver (which would be more capable than Altium’s, for sure) is more than the price of Altium…
Given that an FPGA can output a lot of diff pairs at pretty high speeds these days, even us hobbyists can have a need for this sort of tech.
99% of the time, I’m routing CMOS logic, i2c, SPI, maybe a CAN network here or there. I have maybe 10 projects where I worked with anything so critical that it required the most precise diff pair length matching. I think SRAM was the only that actually was affected by lackadaisically ran diff pairs.
Even then, KiCAD has successfully guided me to routing a number of signals that are capable of data transmission well into the megahertz range.
Designed gigabit Ethernet board and one with FPGA+DDR3 using KiCad 5 and it was ok. Don’t see benefit in OrCAD or Altium here. Maybe for 60 GHz there might be some benefit. Bet that’s not my working frequency range.
The price of a standalone field solver (which would be more capable than Altium’s, for sure) is more than the price of Altium…
Given that an FPGA can output a lot of diff pairs at pretty high speeds these days, even us hobbyists can have a need for this sort of tech.