Be very wary of moving abroad if you have a lot of pension money invested.
If you move outside of the EU, you will not be allowed to take the NI contributions you have made, which make up part of your pension. They will be lost forever, so if you then come back, you cannot pick them up again. The same could apply to your employers contributions.
If you "retire" outside the EU then there will be no annual increase in pension, so that needs to be considered also.
Most Countries will give you a right of residence as opposed to citizenship. Treat this VERY carefully as a right of residency will only apply so long as you are in employment. It will generally only confer emergency medical treatment and will give NO right to state benefits, such as pensions, long term healthcare, non-emergency medical care, etc, etc.
Rights of residency are also normally associated with sponsorship by an individual citizen or by a Company
If you move with one employer asnd then decide you dont like it, then when you resign you could well find you have no right to remain in the Country UNLESS you can gain sponsorship. Your new employer may well NOT wish to pay those charges.
With regards to Holidays, the UK has some of the best paid leave arrangements in the world. The US pay only 10 days, even to their top people and the work ethic is very much different. They have no national health system such as ours and their basic healthcare system really is basic, so much so that some "Third World" Countries have better arrangements. If you lose your job there are no state benefits in the way we know them as you are expected to make provision for yourself. Similarly with healthcare, you have to take a healthcare scheme or work for an employer who will contribute to one.
Finally do not think the grass is greener. Most Countries in the World are in some form of deep economic recession (the except in South America) and in much the same way as the Brits blame all their ills and lack of jobs on "foreigners", remember that YOU are now the foreigner. Many Countries do not have laws like we do and you can find yourself unpopular. Again depending upon where you work, as a foreigner your security can be a serious issue for you.
Where I am working I need to be accompanied by "minders" for example, and the residents tend to live in enclosed communities, which although being luxurious, does mean you cannot simply go and walk down the streets at night in some areas, similarly when you drive you have to use a car with darkened windows.
All in all, you need to do a lot of investigation before you make the decision, it really is that big and the way back is not so simple.