I have used both (Wacom and Laptop w/Touchscreen-(converts to tablet)...
I'll edit in the model#'s and links
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Size does Matter!!!]
I need to look at the model you are interested in. "Large" at least sounds good. My first Wacom had way to small of a work area, and I truly regret purchasing it. It just made everything extra difficult.
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Wacom/Windows: Drivers and concerns]
I'll have to read some reviews of current products, and
I'm assuming Windows 7 (If not... please post your OS). In the past I have been dissapointed with Wacom's lack of either fully testing their drivers, and/or not providing updates in a reasonable time-frame. I had several issues with regard to buttons and other User-Interface devices not functioning properly; (intermittent, not at all, too sensitive without enough functional [config settings/range settings] via Wacoms software). I've looked at some recent Wacom tablets and while "some" of the features (buttons, sliders, keys, analog stick etc...) look helpful,, I am not confident (given my past experience) that they work out of the box; AND have a functional amount of adjustment setting to suit different project types. I'll explain more about that if need be. Hopefully they have gotten their act straight.
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Wacom: The Pen itself]
Luckily I found a hack where I was able to get a 3rd party stylus/pen to work with my Wacom tablet. This is also something I hope they have improved. The nub/tip wasn't versatile enough in size/accuracy to accomplish everything I was hoping for. Great for general brush strokes, but sometimes unusable for fine pixel art, or vector painting like in Ink Space
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Laptop w/Touch-Screen -(Converts to Tablet)]
I had a laptop with touchscreen capability. (unfortunately at the time (4 years ago) widescreen wasn't as common).
I'll edit in the exact model w/ link.
The laptop allowed for twisting the screen 180 degrees and closing the lid. OS was windows XP, and IIRC there was no multi-touch capability (that would have been nice).
It was so much easier to work right on the image itself than it could ever be with my Wacom. For me personally, working right on the media via the touchscreen, inside whatever art/modeling package, was way more intuitive and productive.
That said, the only time my Wacom got any use was when I was tracing in non digital media for either reference or finsih work.
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~ZENassem