Does not matter. The Vendetta either only gets hit on 6s (much better defense than a Sentinel) or has an automatic 5+ cover save (the same thing the Sentinel gets with its smaller profile). The only "advantage" of the smaller profile would be the ability to hide out of
LOS entirely, but if you do that you aren't shooting and are wasting your Sentinel.
more hull points
Which is offset by the significantly higher cost and lower durability. This is what I mean about ignoring the big picture, you and Ailaros look at single attributes (which has more
HP) instead of the big picture (which is harder to kill).
tarpitting
Much less effective now that you can voluntarily fall back if you can't hurt a walker and grenades don't hit on 6s anymore. And if you tarpit you can't shoot, which means your expensive guns are wasted.
being able to shoot on turn 1
Being able to shoot on turn 1 doesn't help very much when it comes at the cost of being laughably inefficient the rest of the game. A Vendetta shooting once on turn 2 does more damage than a pair of
LC armored Sentinels (roughly equivalent in price) do on turns 1 and 2 combined, for 10 points less. And over the following turns the Vendetta dominates by a huge margin.
It is baffling how people can compare an apple to an orange and claim one is objectively better in every situation.
Because the Sentinel is trying to do the same thing as the Vendetta, it just sucks at it. It isn't apples and oranges, it's apples and rotting worm-filled apples.