Commencal Meta HT AM Origin Size question

Looking to purchase one of these bikes this week, someone said they are a small make, I wanted to go for the Medium frame with the 29F/27.5R

I'm approx. 178cm which brings me under the 180cm limit for the M frame according to their site, but when I emailed the rep said to size up to the large which starts at 178cm.

Does anyone think I'll have issues with the M frame or is it best to go to the 29er Large frame?