The Miura VS swaps out laces for a Velcro closure system. This is relatively superficial as far as performance, but is, in my opinion, a nod to the fact that the VS is catered more toward the sport climbing crowd who primarily climb hard single-pitch and like the easy-on, easy-off of Velcro.
Functionally, the primary difference between two shoes is that the Miura VS has what La Sportiva calls their “P3” system incorporated into the shoe. The name stands for “permanent power platform” and refers to the stiffer plastic platform located mostly under the toes, up toward the edge of the ball of the foot. First introduced in earlier La Sportiva models like the Testarossa and the Solution, the platform dramatically stiffens the lower half of the shoe and attaches to the “slingshot” rubber that wraps around the heel rand to keep your foot in place.
The presence of the P3 system accomplishes several things at once: the more rigid material helps maintain downturn (from the arch to the toes) not only during use, but also over the lifetime of the shoe. (The downturn in shoes notoriously disappears in shoes once they are worn, stretched out, and the material fatigues after extended use.) Second, the stiff toe platform makes standing on credit card edges slightly easier, as the foot gets better leverage than is the case with a softer, more pliable material. These are both great improvements for people who climb overhung or techy vertical routes. Lastly, at the risk of stating the obvious, the stiffer toe platform also decreases sensitivity slightly, though I personally haven’t found the decrease to be significant enough to affect the way that I climb.
Because these improvements are achieved through stiffening the sole to maintain downturn, they come at the cost of making the shoe slightly worse at smearing on slab (because you’re fighting the downturn when you smear), and they can be harder on cracks (more on that in a second).
People who loved climbing trad in the Miura lace will likely be as disappointed as their slab-master friends when it comes to the Miura VS. The Miura lace work in cracks largely because the pointed toe box of the shoe fit (at least partially) into finger-sized cracks and could be twisted and locked off to gain some stepping power. But climbing cracks smaller than perfect hands (which can really be done in any shoe) requires the ability to torque the rubber against the walls of the crack; stiffening the business end of the sole, as is the case with the Miura VS, inhibits this ability.
Plus, the persistence of the downturn requires slightly more deliberate foot movement to get your toes into the crack in the first place. So the addition of the P3 system makes the Miura VS an unattractive option for these types of climbing. While I can climb both cracks and slab in the VS (it is not utterly incompetent in these areas), it’s a little bit like forcing the square peg in the round hole: these shoes are not designed for that sort of terrain, and I wind up wishing I had something else on my feet.
I don’t want to sound too harsh with this last point. I think that instituting these changes is a great idea on La Sportiva’s part. The reason for this is somewhat subtle, but it hinges on the fact that though the Miura was used by both sport climbers and trad climbers, it was never really “competing with itself,” if you will. People who chose the tighter sport fit, and people who sized up to a comfortable fit that could be used in cracks, were taking advantage of entirely different aspects of the shoe in the first place. So much so that it’s almost as if they were wearing entirely different shoes, determined by how they were sized to perform. La Sportiva apparently realized this, and concluded that they could improve upon the sport climbing elements of the Miura lace at the expense of the shoe’s ability to climb cracks without (almost) anyone really caring. After all, if you used the original Miura as your sport climbing shoe and sized them tight, you probably never climbed a handcrack in them because of how painful that would be been given your slightly curled toes.
If your shoe quiver is in need of a technical face-climbing workhorse, I don’t know that you can do better than the Miura VS. The stiffness of the Velcro version, relative to the lace-up Miura, accentuates the Miura’s already well-known ability to edge and grab small features. People in the sport climbing camp (like me) won’t bat an eye at the loss of crack climbing prowess (since I never used them for cracks in the first place), and will applaud the edging improvements of the Miura VS. For those in the sized-up trad/crack climbing camp, well, stick with the Miura lace.
(Click to see Marci Eannarino’s take on the La Sportiva Miura VS Women’s)