Hi buddy, welcome.
What type of work will you do on it, cause "engineering" is a very broad term.
I am a mechanical engineer and bought my Surface Book for similar reasons (though my budget limited me to the first gen i7, 512, 16, dGPU.
I mostly do 3D designs, simulations and assemblies. I used to work with a little bit of image editing but not with my SBook...
I work as a freelancer, so mobility is crucial. I got the Bluetooth Arc Touch mouse, however I don't recommend it for work or gaming. It is a nice mouse and I had the original with USB receiver, but it is not as comfortable for extended periods of time, and the middle click is not as reliable. I do recommend you getting a nice mouse even though the touchpad is excellent.
Regarding software, I use SolidWorks and SketchUp for 3D. I have an old Xbox 360 with kinect which I turned it into a recreational 3D scanner (using "Skanect" and some drivers)... I have a 3D printer, and for slicing use Adobe software..
Now, using the Book in clipboard mode I discovered a great 2.5D app called "Wedge" that I allows to sketch with the pen easily and turn it into a simple 3D part. Very nice for sketching ideas while laying in bed.
For image editing, I'm learning "Gimp" and "Inkscape"... I used to work with Adobe Cs, but now I like those free alternatives...
I use Audacity for simple audio editing.
Make sure to personalize your Pen & Ink Workspace settings... I use it ALL THE TIME, and it is great for doodling, expressing your ideas and sharing them with coworkers or clients.
I love Fresh Paint... I started using it with a Surface Pro 3 I had for a while...
Also as an engineer you would appreciate "Principia" it is sort of a game but not really... It is as if Lego's Technics were digital... With tons of mechanical, electric, electronic components to play with and create machines, simulations, games, etc... I had it on android but now I love it on the Surface...