Their code is likely to be less buggy if they copy the tried and tested code and only modify small amounts of it themselves.
LOL. As if...
In realty they've made a hundred tiny commits "reformatting" a couple lines here and there, seemingly to obfuscate the changes.
The diff against the Bitcoin Core they forked from is: 551 files changed, 54096 insertions(+), 47943 deletions(-)
The diff against Bitcoin Core master is: 813 files changed, 76156 insertions(+), 63863 deletions(-)
Does anyone if BitcoinCash contains the malleability-problem fix that SegWit has?
It doesn't, its still fully vulnerable to tx malleability. Though it does copy the signature hashing algorithm from segwit (LOL so much for their concern trolling about segwit being 'patented') it applies it in a way that leaves the malleability problems.