No engine is "flawless". I'm on the other forums too. There are problems here and there, but if you polled the LM2 owners I think you would find that 98% of them are super happy with the product and have basically had no engine related problems.... that's not too bad for a totally new engine design....
There may be some confirmation bias at play there. Hard to know for sure unless there's real data re: LM2/LZ0 vs. L84/L87 failure rates.
I've got a GM mechanic for a best friend that would disagree with that statement based on what he sees come in and come back repeatedly.
You would think that if the L84/L87s were failing at a similar if not greater rate than the Toyota V35A-FTS, they would have a recall and be replacing engines. Are fleet users encountering an alarming rate of failures (ie. across the police fleet)?