I live in Ballachulish and have been walking in the hills in winter a bit in a pair of older Scarpa Manta Pro (Blue Nubuck) and G10's. I've also been trad/sport climbing up to HVS/6b ish and friends have asked if I want to go winter climbing a bit and I'm keen to try. I got a good deal on some Petzl Lynx and am looking at getting a new pair of winter boots. They'll predominantly be used for winter walking with bits of climbing thrown in (probably seconding grade III/IV max for a while).
I'm unsure whether to get some new Manta Tech as they'll be better for walking in or to get some Nepal (or other B3) and use my old Manta's for walking mostly (or use the B3s for walking if they're OK for that).
I'm a bit unsure of the best compromise so I thought I'd see what the collective wisdom thinks and hopefully avoid other people's mistakes.
your current Manta's will still do all your asking of them for the moment and at those grades. Only downfall is that there not as warm as a B3 boot so in cold conditions standing at belays might be too much for them. La Sportiva Nepal's are an excellent bullet proof B3 boot, but they tend to be a slightly different fit for the same size than the Scarpa's, only way to tell is to go to the shop and try them, which at the mo maybe difficult! I for sure wouldn't recommend using a B3 boot as your walking boot. The new manta certainly looks a good boot on paper, my only concern is have they improved the warmth as they say they have!