I should say that I have seen only a few machine-sewn kilts, so my experience with them is limited.
(I must also add here that I have a strong bias towards traditional kilts)
I have seen several hand-sewns that have visible stitches and seams...

I do not mean to cast apersions on either technique, or on any individual's product....

The take home message, in my opinion, is that there are kilts manufactured with machine or by hand that will be of lesser quality than others made the same way....

Once again, it comes down to the practitioner, and not the practice.....