Except having Vales shield still won't matter as much when you can run around with 60 damage cooking pot.
Amusingly enough, apparently spell-book tier weapons are available for the max damage reforge as well. This applies to the HEM as its not considered a 'true' shield (Will NOT ping under defense with magic/ranged under NO circumstances).
With points to the two shields to use for endgame-tier, its a toss-up between the HEM and the Guard cylinder. HEM makes it so relying on natural defense instead of mana shield, which is viable in many situations, is less needed. It however lacks in defensive-stacking with MS, due to not being a true shield. It apparently according to the KR item simulator, and I will have to check with a friend as well, gets max damage reforge, so that is a bonus as well.
Meanwhile, the guard cylinder's biggest things are the alchemic utility you can use, life-drain for instant hp increase when needed, much more useful with defense+heavy armors rather than the ms-based HEM, and as Kaeporo said, has access to many of the defensive alchemy at a short notice, with even faster switching to heavier alchemy.
The only other shield I'd ever consider using would be a targe/demonic fear shield for pingmaster without resorting to indigo candies, which are harmful to you as they disable defense so you can't pretend you're a fiona. And this is speaking from an elf. I cannot consider the Vales shield and the usability of charge even with renovation+avon seems minimal, and this is speaking from a mostly wand+offhand perspective, instead of lance+off as a giant, or the rare x+board as a human/elf. There are situations where defense is more effective than blaze-dodging (I can technically timing it correctly blaze dodge 4/5 thunderstrikes if I ignore the first bolt via stun reduction methods and actually aren't locked to oblivion. Its much better to defend however.)