It is a personal choice; It also depends on what you mean by "best".
As an example:
The "best" education can be bought, and the least expensive education may not be the best, or the worst.
It really depends on your own criteria.
The economy is better in Canada, jobs are difficult to find in the USA, there have been riots in the UK.
No one place is perfect, there is always a trade off.
Ask yourself, what do you really want, make a list of your top twenty choices (in order of priority).
Also ask yourself why do you actually want to move?
If all you want are the free or low cost benefits, then you are trying to immigrate for the wrong reasons.
Immigration is about sacrifice, difficult times and a lot of hard work - if you are not prepared for that, don't try it.
I have seen plenty of people who think that everything will be wonderful, most fail miserably, in some cases they lose money, homes and in extreme cases, family. Over the years there have been countless people in the fora who have separated or divorced during the application process, it also happens when people actually arrive at their destination of choice.
No matter what country immigrants choose, it is not all bad, but I know that life is certainly not easy.
IMO - Immigrants need a reality check before they immigrate.