You have to look on a case-by-case basis. There are hardmods that are clean, stable and a breeze to use, hardmods that require fiddling or the perfect firmware. Some softmods are a mere matter of clicking "ok" while others require multiple attempts or have reports of bricking.
If given the choice, I think most people would want to go with softmods. It doesn't require purchasing things from shady sites or a steady hand (soldering may not be as hard as it may sound, but I don't want to try it out myself), there's usually more feedback in terms of support, and depending on the type it may also be updated more often.
What are you clowns on about? Hacking your console voids your warranty, period. This whole "the warranty isn't voided if they can't detect it" is just a childish attempt to justify something illegal*.
*note: the actual hacking might not be illegal (depends on the country and what you actually do after hacking it), but afaik every console and handheld of the last few generations have explicit wording that the manufacturer's retain the right to void warranty in case of tampering. Most hacks also note this same thing in their documentation, btw. As such, sending back a broken console after hacking - even if the problem isn't related to the hack to begin with - is the exact same fraud as attempting to have a console repaired that's outside the warranty period.