The Manta M4 has been discontinued. If you're looking for something new, check out the best mountaineering boots for 2020.
Excellent full shank all leather hiking/mountaineering boot, takes C2 crampon, beautifully made, break-in period is bit tough (3-4 months) no blisters though. Now after 10 months they are superb, so comfortable, great support, agility, and feel great.
Excellent for hopping around on the rocks at high altitude or for fast descents, useful for climbing too as sole is very stiff. Not great on approaches when breaking in, but ok now. They look great still, the reversed leather means no scuffing as with traditional leather. This is not a boot for approaches or general walking but is superb for heavy backpacking rough trails or entry level mountaineering.
I think the RSN last suits slightly slimmer foot that I have and I do find Scarpa's a little on the small size. As for toe box curling and shortening I haven't experienced that yet and have done well over 100 miles over very rough terrain. I'm using superfeet hiker green insoles which work great, but I do concur with previous review, don't go for anything thicker than superfeet as the ankle will roll. I use Bridgedale socks I find they are excellent. I'm looking forward to many years pleasure from my Scarpa Mantas.
Use: rough trail heavy pack
Break-in Period: 3-4 months
Price Paid: £143