I've got Manta Pros and only wear them in the snow. They're heavy and warm so they'll make the walk harder and your feet will sweat so there's a higher risk of blisters, especially when they're new. I found I had to adapt the way I walked with stiffer soled boots, which makes sense on winter routes but less in autumn.
Another thing to consider is the deep tread which is great for walking in snow, you don't want to wear that out by wearing them all year round - ie you'll get more winters out of them if you save them for when they're needed. I wore the Mantas on SCNL at the end of Feb and a pair of trainers on the Buachaille just after the 5 mile limit was lifted.
Mantas
trainers