A better option... if someone else is paying for it. It is literally ~10x the price of a 1080ti ($700 vs a suggested $7000).
The DGX1 (w 8 P100's) is another example of an overpriced, turnkey money extraction "solution."
Also worth noting it's hard to get a Ti non-founder edition, which has a hefty premium on it for the privilege of being first. The regular 1080 non-FE cards are probably the best bang/buck right now.
Folking doing ML/AI/DL, or any HPC really, gotta profile their apps to find bottlenecks and root out resource waste: single prec math? ram? algorithm complexity? storage iops? network latency? etc. because throwing money at a problem is no substitute for having a clue how to use money, time and electricity wisely.
Feel free to invest your time and money into building and debugging issues on your own system. Companies which pay big $$$ to their data scientists have different incentives than regular users - you do not want to waste time of your expensive staff on chasing hardware/software issues.
Saves you debugging your way to a workable 8*1080ti, when you look at it from this angle. Not sure if being able to swap out the cards is what makes building them yourself worth it in addition to the cost saving.
If you require non-trivial communication no PCIe setup would beat NVLink communication bandwidth on DGX-1.
If you are allowed to buy one. Nvidia doesn't have nearly enough chips to meet demand, the bulk of their production has been earmarked for quite a while ahead, what little is left over and makes it into the DGX-1 is sold to very few hand picked customers.