One of the issues plaguing all gated corner rounders is the fact that, once the card has been stripped, it's corner is no longer 90 degrees. This immediately begs the question, "why do all gated, playing card specific corner rounders have 90 degree gates"?
Of course, a card that isn't 90 degrees won't cut a clean corner if the gate you're forcing it into is itself 90 degrees.

It is, simply put, a major design flaw of all playing card specific, and crafting-style corner rounders released to date.

Even the Rolls Royce trimmers, such as Joe Porpers $3500.00 trimmer, suffered this malady (I owned one, and this was most definitely an issue) ... a malady which results in dissimilar corners on each card cut. Note that I'm talking about making efforts to achieve the level of perfection one would expect of expensive corner rounders/card trimmers here ... I'm sure that for many magic uses, the Chinese rounders off Amazon would continue to work just fine, especially if ones standards and/or requirements weren't high.

https://theperfectshuffle.com/Stripper_Fixer/
So Eoin has finally fixed this issue by creating a machined corner rounder that has both 90 degree gates, and an "open" gate that allow for non-90 degree cards to be trimmed perfectly, and with absolute consistency.
Note that this "open" gate is not like the inexpensive style of corner rounder with no gates at all.

This is the first corner rounder of its type by my reckoning, I've not ever seen anything like it ... and indeed the way one worked around this issue previously was always to find a cheap corner rounder that has no gates at all and "freehand" it ... which unfortunately requires far more skill and dexterity than most have, unless you're gaffing dozens of decks each day, and have a well developed muscle memory such as you can freehand an un-gated corner rounder accurately.

Very nice and priced right too!

Eoin corner cutters seconded here, they are excellent and as said good for the price