We had a non-pro Intuos M for less than a year now and were very happy with its ease of use, and the precision by which we could enter data with the pressure-sensitive pen. It is a very good value for money digitizing tablet for the occasional or semi-professional usage. We do recommend it.
After less than a year we still made the switch to the Pro version simply because of the many additional features it has:
- twice the resolution of both, the tablet, and the pressure levels
- eraser function on the pen
- tilt-recognition in addition to pressure
- a much thinner design that makes drawing more comfortable
- pen with a more ergonomic grip to it and with a solid base it can rest on
In addition the pro tablet has many options that don't come to mind at first. It is wireless (Bluetooth), has multi-touch gesture recognition, is upgradeable e.g. with a paper-holder (think of your grid lines!), or can have different surfaces with a different roughness to them. The latter also gives us the possibility to replace the surface when it is worn out after a while. All other replacement parts appear to be much easier to get too, be it a replacement pen, or pen-tips. Most shops sadly have these for the Pro version only.
We feel that the silghtly larger dimensions are more than compensated by the thinner tablet, and by the base for the pen (that otherwise always was somewhere else).
We also don't miss the grid at all because when drawing you keep your eyes on the monitor anyway. If you need a grid, then consider the paper-version.
If however budget matters then if you don't actually use it for drawing but simply for a mouse replacement, and to see how much you may need the tablet at all you will be happy with the non-pro version too. Some features of the Pro version may also need the approproate software to support them (we use Gimp).