Ask HN: Job Advice

So I am going through a scenario. I was working in a startup for the last few years and my salary, due to personal relationships and negotiations have been much much lower than industry standard. I was given 1.5% equity when starting and also flexible working hours and the freedom to take days off whenever needed.

Few weeks ago, I applied to a new company just to see what it's like and I cleared it and was offered around 4 times the current salary. When I notified it to the current employer, they offered me 8% of shares to stay.

I am now confused on what to do, because on one-side there's a sure financial benefit, but maybe stricter timelines and procedures and on the other, there's a possibility of high magnitude of benefits if the current company grows. I'd like to hear your thoughts