I haven't noticed any lag, personally. I don't draw too much in Photoshop, but when I use filters and dialogue options it is a little slow, but I always attributed that to either my large files (high resolution) or perhaps the low specs. For serious Adobe creators, 16 GB of RAM is still on the low side, especially when video editing. Unfortunately, there's no upgrading the unit, so it's stuck with whatever it comes with.
In the future, I do plan on building a computer with more impressive specs and a Wacom Cintiq for the monitor. Not as a replacement for the mobilestudio, but when I am at home or working on a large project, it would be nice to have the larger screen and better performance. The mobilestudio will be used whenever I am not home.
It makes sense, 16 gb is definitely on the low side. I have a surface pro though, full specs, and it ain't that bad! For work at home i have a more powerful desktop pc, with old cintiq 12". When i can afford a new one i'll just get the screen type i guess.