I have considered investing in a screen tablet but I just don't think I'd honestly like it as much for the price difference.
It's only my experience here as many people LOVE the Wacom Cintiq but I was given one by a company I was doing some work for.
I was really excited about it but it just didn't work for me and spent almost a year in the cupboard.
They are a pretty chunky bit of kit and you need a big and dedicated workspace to keep them permanently.
These things are just not portable in any way and you need to use them with your computer as whey aren't really that stand alone.
The cables are pretty thick and there's quite a few of them and I think there was a power brick too.
They don't show you these in the reviews.
Also, they are rather expensive.
I was also given a pretty high end MacBook Pro to use with it and it made it's fans blow to the point I feared it may give up the ghost.
It may have been my fault for not taking the time to set it up properly but all the things like the UI, folders and menus were displayed REALLY small to the point where I had trouble seeing them.
They don't really work with Illustrator that well apart from the brush and pencil tools but I guess they come into their own in Ps for digital painting.
At the same company I had a go with the iPad Pro and that was amazing and everything I hoped the Cintiq would be.
They ended up selling the Cintiq's and buying more iPad Pros.