You need to check out each individual establishment, as some places use different words to describe the same thing, or the same word to describe different things, so don't assume all "Nurseries" or all "Pre-schools" etc., are the same as each other.
As a rule, a school with a Nursery class, or a stand alone Nursery school (but heed the warning anyone can call themselves a Nursery school - I'm talking about those maintained by the Local Authority), will have a qualified teacher in charge - which people tend to like. This does mean, however, that they will have a ratio of 1 adult : 13 children.
A PVI (Private, Voluntary or Independent) Nursery usually won't have a teacher, but will usually be staffed by NVQ qualified Level 3 staff (+ level 2s and apprentices), however, there will be a ratio of 1 adult : 8 children.
School Nurseries tend to be a bit more dictotorial on the hours you can have - so they will usually operate only within school hours, and many will dictate that they either split mornings and afternoons, or that all the dc do 2.5 days each. This may, or may not suit the rest of your life. PVIs can often be a lot more flexible about which days and hours you have.
Both ought to be following the same curriculum (EYFS)
Going to a school Nursery or not, has absolutely no bearing on if you will get a place at that school in Reception.
Some schools have Nursery groups on site, which are actually registered as PVIs.
Some schools have started confusing the issue still further over recent years, by registering to be able to take 2 yr olds as well.
It really is a mindfield 
So the best advice is to find out a 'shortlist' (probably those you can get to easily) then go and look round and ask them the questions. If you are not sure where to find out where they are, then contact the Family Information service at your local authority (Google FIS + wherever you live) and they will let you have a list of local Nurseries. Children's Centres will also have a list of settings in their locality.