Before I changed to full leather, literally EVERY single person used to comment on how crap the tartan seats looked, I had the following kinds of comments;
"looks like a granny's knitting pattern"
"Looks like the top of a biscuit tin"
"Looks like a tartan kilt"
"Looks crap, old, awful" etc etc
My personal opinion, was I thought it looked ok! Quite retro! - Most of the comments were from women as well!
I didn't change because of the pressure of people saying how crap it looked though!
I'd personally prefer the tartan for the summer and the leather for the winter!