I have a 20-year-old FT817 and a 5-year-old KX2 with internal ATU.
I wouldn’t use either in the rain without protection. Yes, the KX2 is more delicate but I wouldn’t like either to fall onto rocky ground. So, I carry both in protective bags inside my rucksack and when operating, they sit on or close to the ground or – if I can find one - on a safe ledge.
The weight comparison is a thorny one and has been discussed here many times before. I concluded there’s no ‘one size fits all’ answer. I understand why some like ultra-simple / ultra-lightweight radio but for me my rucksack has a lot of other stuff this time of year including a tarp or a bothy bag, winter clothes, food, hot drink, etc, which masks the small weight differences between rigs.
Unless I’m doing 2m/70cm SSB/CW [sadly, rarely these days!] or 6m I always take the KX2 and not the 817. I throw away the KX2’s weight and volume advantage by also taking my FT1D HT (with Diamond RH770 ½-wave whip). Why? I like the redundancy which has avoided having a failed activation on a few occasions.
A lot of useful comparisons here: