Question: I am in the process of leaving my PhD programme in life sciences at a top university in the UK. A PhD is simply not for me and I find the work/life balance to be intolerable; in addition, my PhD so far has included an industrial placement at a fortune 500 company that was very eye opening and enjoyable.

My question is whether it is better to leave the fact that I quit a PhD off my CV, or to have the failed PhD / MPhil on there, or to mask it as '18 months of lab experience' or something similar. Is it possible to make the fact I left a PhD sound good?

Answer: 
I went through the process of leaving a PhD program just before the dissertation phase. I have not experienced any negative impact from this in job searching or interviewing. In fact, in some cases the interviewers have joked about how leaving early must imply that I actually have some common sense.

[I wrote up some thoughts on the mathematics StackExchange site that might be relevant for this thread too.](https://math.stackexchange.com/questions/44704/how-to-study-math-to-really-understand-it-and-have-a-healthy-lifestyle-with-free/129430#129430)

In general, just be honest. Try to leave your PhD group on the best terms possible. Connect with peers and professors as much as you can before leaving (via LinkedIn, or swapping emails, etc.). Ask them point blank if you can count on a positive reference if you ever needed one.

If you leave on bad terms (e.g. your adviser is furious that you are leaving, or you leave without completing a certain milestone that causes everyone else to absorb more work) then it can be trickier but still not impossible.

Be honest when describing your motivations. Experiencing industrial work settings and preferring that to an academic setting is a very mature and valid reason to switch. If someone holds that against you, then you get free info that they would be a horrible boss.

I do list my lab experience on my resume. I completed several useful and interesting projects in my time as a PhD candidate, so I like to talk about these during interviews if I can. Having them on the resume does sometimes lead to confusion, so just be sure to practice a nicely worded and clear statement that explains why the resume items are there and what your thinking was in terms of leaving the PhD program.
There is no need to make quitting PhD sound good. Be honest and let them know why you quit. The problem with providing partial information like "18 months of lab experience" is, if during the HR round, or during a background check, your employer comes to know about you having quit/failed PhD, it'll reflect worse on your personality. 

Just let the employer know why you quit and highlight your skills and achievements. That would at the least save you from any future embarrassments.