Definitely get the 256 gb. But there's a 50/50 chance you will have something wrong with your SP3 - loud fan, low battery life, over heating, waking/sleeping problem, keyboard problem, random **** freezing, etc. I own one and I know a few people who do and about half of us had issues. I browse the surface subreddit a lot and 77.6% of the posts are issues people are having.
The issues I personally had were minor but it was very annoying and impeded my productivity on many occasions. That being said it's an amazing machine. SP3 + onenote for medical school is awesome. I accidentally broke my screen and didn't have my SP3 for a few months and I wanted to kill myself after going back to using a regular laptop + physical books
I never used my physical copy of First Aid or Pathoma, I just send the chapters into onenote and annotated it there. For the 3 months or so where I didnt have my surface I had to do everything on the physical copies and the tablet way was much superior IMO - theres no worry of losing your book or spilling coffee on it since it's automatically backed up. You can copy + paste images, diagrams, important info from wikipedia and supplement First aid or your lecture powerpoints. You can ctrl+F and find specific things. Sometimes you annotate in your physical book in pen and **** up really bad and you cant erase it. Also annotating in physical first aid is terrible because there's barely any room (I see my classmates with a million postit notes and papers stuck into their first aid ew no thanks bro), while you have infinite amount of writing space on the SP3. Insert textbook chapters into onenote and write all over it if you want. Currently using my SP3 for Uworld/STEP studying and I can send all the high yield explanations and diagrams and charts next to the correct sections in First aid. Also I can hop from tablet to my desktop or vice versa since the notes are all synchronized. Also never having to print out a physical copy of a powerpoint ever again (if you're a lecture type of person)
Cons: I hate using it as a laptop on my lap but its fine if you have a flat surface. Also most windows programs arent optimized for tablet use so it takes some getting used to
6 months ago when I had my buggy tablet, I would have probably given it a 5.5. I loved using a tablet but the experience was bad because of the bugs and I would have recommended you look into the Surface 3 instead. I ended up getting my SP3 replaced and the replacement was 100% functioning with no bugs. Currently using it for my STEP studying I would rate my current experience at an 8.5 out of 10.
tl;dr it's great if you don't get a buggy machine