The Blade is a tried-and-true baseliner's attacking control stick that works for a myriad of mechanicals styles, but predominantly biases towards flatter hitting. It has a (mostly) true feel and a (mostly) consistent string bed with a hallmark hoop-centric mass-distribution, for those who really like to play with more tip awareness, head-heavier balance than average, and who have full, well-developed stroke mechanics and at least a modicum of adult strength and conditioning.
The Shift is Wilson's attempt at a baseliner's attacking tweener that offer's Blade-like precision with Clash/Burn -like power level, to deliver more pace and spin at lower weightings / effort level. To do so, it employs a thicker 23.5mm constant beam (2mm thicker than the Blade 98, 1.5mm thicker than the Blade 100), and a dual flex profile, flexing softer like a player's stick in the lateral plane (across the face) and firmer like a Pure Drive in the longitudinal plane (from face-on). It comes in three weightings (99L, 99 and Pro) and two string patterns (16x20 on the 99L and 99, 18x20 on the Pro). And the outcome, especially compared to conventional frames, is one of surprising levels of spin with decent power and control. That said, it's not all roses and unicorns, as there's a fairly black-or-white tipping point between the two flex profiles, and as such, the Shift is really 1) best meant for people who hit with as much swipe as possible and 2) often erratic for those whose mechanics are flat enough to cause their swing to routinely pass between both planes of flex in a single stroke (confirmed by enough legit reviewers to be a real thing, not just conjecture). So while the v1 is a decent first attempt, IMHO Wilson needs to go back to the drawing board and figure out to better blend the two flex profiles for a more reliable rebound response in any axis of motion. If they can do that, then they'll have true fire on their hands. Until then, you'll have to be a specific type of hitter to really exploit the advantages of the v1, while also avoiding its potentially erratic nature.
Long explanation short: if you were on a desert island, couldn't demo, had a tournament for your life tomorrow and could only choose between Blade and Shift, more often than not I'd go with which permutation of Blade 100 fits your strength level (100, 100L or 100UL), or 98/98L if you're skills/strength are sound enough.
Hope that helps. Any questions, feel free.
