Precise details on what I mean by "serious competitors" below.
Wacom recently announced the Cintiq Companion 2. It's a laptop-sized pro tablet that can run all design software including Adobe CS6/CC and basic 3D graphics software (running Windows 8.1), and it has a built in pen & touch screen that is the same as Wacom's latest regular Cintiq and Intuous range.
So, you can pull it out of a bag and start drawing or designing with virtually anything you use at home or work. If you have a higher spec machine at home or work, you can also plug this in to that when you get back and use it as an input device (unlike the original Cintiq Companion).
Before I start saving up (they won't be cheap), I want to check see if there is anything else that comes close. Wacom's patent has expired, and their competitors have been catching up fast, but I've lost track of all the different companies who make things like this.
To cut out any subjectivity, here's the standard I'm talking about. This is based on personal experience with similar devices plus research on common frustrations for designers and digital artists using these (feel free to suggest anything I've missed):
- Capable of running pro design software: at least Adobe CS6 and/or Adobe CC, bonus points for designer-friendly 3D software like e.g. zBrush, Blender, Mudbox or Cinema4D.
- As portable as a MacBook Pro (bonus points for any portability beyond this)
Built in pen digitizer comparable in quality to Intuos Pro / Cintiq. To be more specific:
- Accurate, consistent customisable calibration, so you can set it to the angle you naturally hold your pen at and draw without thinking about correcting for inaccuracies.
- Accuracy is hard to measure objectively, but to give a comparison point, I (and many other reviewers) would rate the Wacom "penabled" digitizers (used in some laptops, many Windows tablets, Mac Modbooks (I believe) and the Samsung Galaxy Note series) as being very nearly but not quite at the "just draw without thinking about it" standard, early Cintiqs also not quite at this standard, but modern Cintiqs comfortably above it.
- No major inaccurate areas (some tablets lose accuracy towards the screen edge)
- Smooth pressure curves (early N-Trig digitizers were notoriously blotchy)
- Editable pressure curves (I think Surface Pros and many other Windows tablets can't be customised, but I could be wrong our out of date on that)
- Many bonus points if it does tilt angle and/or rotation similar to a Wacom Art Pen.
- Accurate, consistent customisable calibration, so you can set it to the angle you naturally hold your pen at and draw without thinking about correcting for inaccuracies.
Many bonus points if you can plug it in to a Mac or PC and use it as a screen and pen tablet device for that other machine
- Many bonus points if it has a replaceable battery. The original Cintiq Companion didn't, and it looks like the sequel might not too (only being able to last one charge is a big drawback for any portable professional gear).