On site for Europe or switch the company and accept the 100% hike which one is a better option??

Switch. Always the best option

What was the client ? and better have in mind how was thier Financials.

Onsite is a lolypop that can end even in 3 months

Switch

Bro

Better Take Onsite...You can save some Bulk amount atleast for a Year..

100% Hike here, will go to Variable Pay and Income Tax.

Take onsite

Go onsite you earn something atleast and having a experience of onsite people will give hike based on that experience also

100% hike from where ? If 10L to 20L go onsite. If 25L to 50L switch within India.
By the way Netherlands is a good country to migrate to.

Onsite

Go onsite.

Come back after 2 years, by now your CTC and experience has improved significantly.

Your hike will still remain at some other company post return.

In 3 years, you will be at a minimum of 250% hike from current plus having onsite in your resume and having a good taste in life at onsite.

Think on these lines.