I have used a Wacom Intuos tablet since 2002; first the Intuos 2 (medium) and for the past 7 years have been using a Wacom Pro S. These are all called Pen Tablets. The image you are working on is shown on your computer screen while the tablet is sitting flat (horizontal) on the desk. It has quite a learning curve because the user is looking in one place and drawing / retouching somewhere else. That being said, the fine control is fantastic and much, much more accurate / sensitive than a mouse. When I first started using these devices, Wacom was the only game in town, but there are a number of other manufacturers around, including Huion, XP-Pen, and so on. The main difference continues to be the more durable build of the Wacom products versus the others, but one pays for the quality.
1. Pen Tablet
About a month ago, I switched to something called a Pen Display. It is essentially a special computer screen that you can draw. Unlike pen tablet, one usually puts these on a sloped stand, which makes them easier on the head and neck. The reviews on some of the competitors, especially the higher end Huion tablets were very good, so I ended up buy a fairly pricey model the Huion Kamvas Pro 16 Plus (4K). The learning curve was close to zero, coming from a tablet and I suspect it would not be a lot longer moving from a mouse-based approach. One still needs access to a keyboard, as this particular tablet does not have any shortcut keys built in. I've configured it so that it is mirrored with my primary display. It has a separate power supply connection and plugs into my video card as well as into my computer with a standard USB connection. The connectors on the pen display are through a USB-C connector.
The devices are compatible with Windows, MacOS and Android.
Because the user's (oily) hand rests on the pen display, a two-finger glove (the baby finger and ring finger are covered).
After a month of using it, I find it far more intuitive than the pen tablet. I am not getting rid of my pen tablet, but will only be using it when I am traveling as it is far lighter and more robust than the pen display. There are a couple of small issues. When using a pen tablet, the image one is working on is never covered by the hand, but with the pen display it is. I could never understand Photoshop's "Rotate View" tool before, but I use it all the time now. There can be a bit of parallax (fractions of a millimeter) issue as well, but the higher end Huion display tablets have virtually eliminated this issue, as the screen and glass working surface have been laminated together. Some of the less expensive tablets do not have this feature (and even some of the more expensive Wacom Cintiq tablets reportedly do not have this feature either). The cheaper tablets use a scratch resistant film whereas the more expensive ones have an etched glass. I can't comment on this, as my experience is with the etched glass variety.
2. Pen Display
If cost were no object I would definitely recommend a Pen Display over a Pen Tablet. That being said, both options are better than using a mouse for people that do a lot of precision retouching.
A third option that I did not consider due to the much higher cost is the Pen Computer. It looks a lot like the Pen Display, but does not require an external computer.
Why did I buy the model I did; because it is completely compatible with my new 4K AdobeRGB compliant laptop.