Can only speak for myself here. Do think its fine to wear other clan's tartans - and I have. Motivation was, as you say, liking the colors and wanting a kilt in that color range.

Over time though, it just doesn't feel right. I've purchased kilts in six other clan's tartans (though one never knows their family tree completely I can only guess I've no clan blood for them). After a while I've sold four of the six kilts and one more is currently offered for sale.

The exception for me is the MacLean Hunting - a beautiful tartan and the tartan frequently worn by Sir Sean Connery. Think I'll hang on to that one.

Point is, for me at least, over time - wearing another clan's tartan just doesn't feel right, even if it seemed a good idea when purchased.

So, how you feel about it when you lay your money down may change when later you're wearing the kilt out and about.