So long as all emulation is turned off and the input lag matches the minimum frequency requirements no human eye will ever notice a difference between a TV and a monitor of equivalent specs. Apples to apples. That being said the main advantage of TVs over monitors in the real world is the cost per inch. If you're happy running at 60hz and want a larger screen you're almost always better off running a quality TV, so long as it has an input lag <16.67ms (which is more common and affordable than it once was). You may even get a 120Hz with <6.9ms but then cost benefit has to be assessed on a case by case basis. If a larger screen is not a concern, you are willing to afford the price tag of a larger monitor or is simply unsure of what to look for exactly when shopping then a monitor is typically the safer option for a dedicated gaming application if nothing else because they're manufactured with the aim to tick the right boxes without the compromises and bloated features a TV has to contend with. Personally I weight: Size; Frequency; Input Lag; Response Time (GTG/BTW); Bezels (if triple screens); RGB/Whites/Blacks/Brightness; PPI and Cost in that order. As long as those match/best what you're looking for you can be perfectly happy with either a TV or a monitor in my opinion.
